A friction regulation hybrid driving method for backward motion restraint of the smooth impact drive mechanism

Abstract

The smooth impact drive mechanism (SIDM) is a type of piezoelectric actuator that has been developed for several decades. As a kind of driving method for the SIDM, the traditional sawtooth (TS) wave is always employed. The kinetic friction force during the rapid contraction stage usually results in the generation of a backward motion. A friction regulation hybrid (FRH) driving method realized by a composite waveform for the backward motion restraint of the SIDM is proposed in this paper. The composite waveform is composed of a sawtooth driving (SD) wave and a sinusoidal friction regulation (SFR) wave which is applied to the rapid deformation stage of the SD wave. A prototype of the SIDM was fabricated and its output performance under the excitation of the FRH driving method and the TS wave driving method was tested. The results indicate that the backward motion can be restrained obviously using the FRH driving method. Compared with the driving effect of the TS wave, the backward rates of the prototype in forward and reverse motions are decreased by 83% and 85%, respectively.

The Asymmetric Flexure Hinge Structures and the Hybrid Excitation Methods for Piezoelectric Stick-Slip Actuators

“…Figure 6(a) shows the working principle of the piezoelectric stick-slip actuator by traditional driving method (TDM), which includes the slow extension and rapid contraction stages of the traditional saw-tooth driving wave. As illustrated in Figure 6(b), the smooth driving method (SDM) is realized by a composite wave, in which the composite wave includes a saw-tooth driving wave (SD-wave) and a sinusoidal friction regulation wave (SFR-wave), in which the SFR-wave can adjust the friction force between the frictional part and slider in resonant mode (RSFR-wave) or non-resonant mode (NSFR-wave) [15]. From the time A to B, the composite wave is equivalent to one part of the SD-wave.…”

“…In terms of structural designs, the axial stiffness of the stator is unevenly distributed, and the parasitic motion is generated by introducing the flexure hinge mechanism into the design of the stator, including trapezoid-type piezoelectric stick-slip actuator [10], piezoelectric stick-slip actuators with asymmetrical flexure hinges [11,12] and mode conversion piezoelectric stick-slip actuator [13]; these structural designs can comprehensively adjust the friction force during the movement of the stick-slip actuator, thereby significantly improving the velocity and load; besides, a coupled asymmetrical flexure hinge mechanism is also developed to achieve the bidirectional motion of the non-parallel type stick-slip actuators [14]. In terms of driving methods, a nonresonant mode smooth driving method (SDM) based on ultrasonic friction reduction is first proposed for the parallel type stick-slip actuator, and the backward motion is restrained during the rapid contraction stage [15]. According to ultrasonic friction reduction, the smaller kinetic friction between the frictional part and the slider can be realized at the resonant frequency.…”

A Piezoelectric Linear Actuator Controlled by the Reversed-Phase Connection of Two Bimorphs

“…At that a voltage of 50 Vp-p, a maximum angular velocity of 18.88 mrad/s and a minimum resolution of 2.8 mrad can be obtained [19]. Instead of asymmetric driving force, FCT actively produces asymmetric friction in the forward and backward direction to generate the travel difference [22]- [25], [31]. Wen et al proposed a new inertial piezoelectric actuator based on the control of the friction force between the rotor and the supporting surface through the use of a triangular block.…”

“…This method can achieve no backward only when the friction force and the driving force are well adapted, but cannot be universally applied to various actuators. Another way to reduce drawback is to optimize the waveform of the drive signal [25], [31]- [32]. Wang et al proposed a driving method realized by a composite waveform which consists of a sawtooth driving wave and a sinusoidal friction driving wave for backward motion restraint of the actuator [31].…”

A Four-Feet Walking-Type Rotary Piezoelectric Actuator with Minute Step Motion

“…Piezoelectric actuators usually convert electrical energies into mechanical energies by using the inverse piezoelectric effects and frictional forces [ 1 , 2 , 3 ]. They have simple structures, fast responses, low speeds, self-locking when powered off, and high positioning accuracies, which give them wide application prospects in robot joints, optical instruments, MEMS, positioning stages, and space mechanisms [ 4 , 5 , 6 , 7 , 8 , 9 ].…”