Consistency finishing is one of the technical bottlenecks in performance-oriented manufacturing for bearing rings, while non-destructive and all-around processing is its core demand. To accomplish ...this objective, a novel rotary barrel finishing approach, which was floating clamp, friction drive, and horizontal limit, was proposed. First, the effect of the vessel rotation speed on bearing ring’s motion and media kinetic energy’s distribution was investigated by the ADAMS-EDEM co-simulation. The bearing ring can realize continuous rotation and be effectively limited within some intervals under different vessel rotation speeds. The media kinetic energy is uniformly distributed in the radical direction. And it can reach the maximum when the rotation speed of the vessel is 40 rpm, which is considered to obtain the best finishing effect. Subsequently, the surface roughness of the workpiece was investigated by optimal finishing experiment. It shows that the surface roughness of bearing ring surfaces can be improved. Moreover, the coefficient of variation of Ra on the inner surface, end face1, and end face2 were reduced to 9.25% to 5.33%, 7.35%, and 5.73% respectively. The research results indicate that the bearing ring surfaces can be finished simultaneously and clamed non-destructive by this finishing approach. This process provides reference and basis for ring-shaped parts finishing.
•Stator textures and rotor flexibility were used to reshare stresses and anti-wear.•Frictional stress homogenization is available after surface texturing.•Stress overloading and subsurface damage are ...released for textured stator.•Directional microtextures assist low-voltage and high-performance driving.•158 rpm and 73 N·mm were obtained at 80Vp of drive voltage and 40 N of preload.
Traveling-wave ultrasonic motors promise widespread applications in precision engineering, medical, and aerospace field due to their high-power density, but suffer from low efficiency and stress gradient. In this case, the synergy effect of surface-functionalized friction regulation and interface coupling interference of wear loss/debris could effectively eliminate these deficiencies. Herein, we report a low-voltage driving rotational piezoelectric motor (PM30) that proceeds through laser-induced microtextured stators coupling with flexible rotors, which enables working at a rotational speed of 158 rpm and torque of 73 N·mm, respectively, under the condition of low-voltage (80Vp) and low-preload (40 N). Such operation parameters are far beyond the current reported results. Furthermore, FEM simulation and SEM observation demonstrated that the low-voltage driving and high-performance output are resulting from the combination of surface microtextured stators for friction enhancement and flexible rotors for displacement amplification with contact expansion, which regulates tangential friction and reshares the stresses distribution during the dynamic contact along with the rotary motion of rotors. This work provides a promising strategy to construct friction-stress regulation and energy-transformation enhancement toward energy-saving and high-efficient friction drive for piezoelectric devices.
This paper provides a comprehensive review of the literature regarding precision piezoelectric motors over long ranges based on the principle of repeating a series of small periodic step motions, ...named “frequency leveraged motors” in this paper. A summary of recent research into frequency leveraged motors is presented. Work is classified into three categories by different frequency driving methods, including ultrasonic motors, quasi-static motors (non-resonant motors), and motors combined resonant and quasi-static operations. Pros and cons of each motor type are discussed in term of their principle, structure, and performance. In addition, future perspectives and improvements of the frequency leveraged motor are also provided. It is summarized in such a way can provide a better understanding of the core characteristics of each type of long range piezoelectric motor. Moreover, it also aids in determining successful designs, suitability for applications and further research areas.
In this paper, the stick-slip motion of a new type of micro-robot with two perpendicular vibratory actuators is studied which is based on the friction drive principle. The actuators are based on ...piezo-electric phenomenon which are driven by a harmonic voltage, and both of them are mounted on the micro-robot body. These actuators cause the micro-robot moves forward or backward due to the specified phase difference between the voltages applied to vertical and horizontal actuators. Since the dynamics of the actuators affects on the micro-robot motion, so to derive the equations of motion the coupled dynamics between the body of robot and vibratory masses of actuators are considered, and the motion dynamics of the micro-robot is investigated by considering the piezo-actuators effects. After deriving the governing equations of motion, the operative parameters of the piezo-actuated micro-robot, which affect the motion dynamics, are defined in non-dimensional forms and studied for the first time. The Fourier expansion method is used to analyze the numerical results, and the discussion about the motion characteristics of the micro-robot is presented by defining the mean velocity and performance coefficient of the micro-robot stick-slip motion. At last, a simple practical model of this micro-robot is designed and fabricated with two Langevin-type piezo-electric actuators, and then the motion capability of the micro-robot is verified qualitatively by test.
This paper presents a data-driven method for waveform optimization of a two-axis smooth impact drive mechanism (SIDM) actuator. The actuator was constructed by two piezoelectric elements (PZTs) ...perpendicularly fixed to an L-shaped base for two-axis positioning. An XY stage was designed and constructed by assembling the two-axis SIDM actuator. The XY stage could position long motion ranges of several millimeters with nanometer-level resolution, and the size was confined to be 20 mm (X) × 20 mm (Y) × 4.5 mm (H). The data-driven method based on the long short-term memory (LSTM) neural networks was used to predict the optimum input voltage waveform of the actuator. With the optimized input voltage waveform, it was verified that the maximum velocity of the stage could be improved about two times.
This paper develops a method for estimating the state of deterioration of a friction drive system and presents its use for predicting and controlling the Remaining Useful Life (RUL) of such a system. ...The friction drive system is assumed to be affected by endogenous uncertainties and exogenous disturbances. The proposed method is intended for on-line estimation of the contact surface deterioration and it is based on a parameter-varying model that includes both the motion dynamics and the deterioration dynamics of the device. Since, in the presented setting, the control actions on the mechanical system play a role on the non-linear deterioration dynamics, an Extended Kalman Filter is developed for simultaneously estimating both the state of deterioration and its associated estimation error bounds. A numerical example is presented to illustrate the interest of such estimations for RUL prognosis and RUL control. The presented example considers the availability of angular speed measurements and the possibility of re-planning motor torques and/or re-planning desired angular speeds in order to control RUL based on RUL prognosis.
This study presents the investigation of translational motion of a surface acoustic wave (SAW) linear motor employing dual friction drive (DFD) through mathematical modeling and finite element ...simulation. The presented SAW linear motor consists of two identical piezoelectric stators facing each other and holding a slider tightly between them. The slider is placed in the path of SAWs generated in the two stators supplied with the preload required for the friction drive, which is capable of moving the slider in forward and reverse translational motion. Typically, the stator contains an interdigital transducer (IDT) fabricated on either side of a lithium niobate (LiNbO3) substrate so that the application of sinusoidal voltage excitation to an IDT generates a traveling Rayleigh SAW on the surface of the substrate. The SAW, in the presence of preload, interacts with the slider and the frictional force drives the slider. By simultaneously exciting two IDTs, one each from the top and bottom stators, on one side of the motor, the slider makes a translational motion toward the side of the activated IDTs. The direction of the movement of the slider can be reversed by switching excitation to the IDT pair on the particular side of the motor. Mathematical modeling and finite element simulation of the motor is carried out to study the characteristics such as step motions, displacement, and forces acting on the slider for different amplitudes of input excitation. Finally, a comparative study has been carried out to show the advantages of the proposed DFD SAW motor over the conventional SAW motor.
Vibration drilling technology has the advantages of reliable chip breaking, smooth chip removal, small drilling force, and slight tool wear. However, most of the current vibration drilling devices ...are special machine tools, or the existing machine tools are transformed. The problems of high cost, poor universality, and difficult parameter adjustment limit the further promotion of vibration drilling technology. Based on the principle of friction transmission, this paper designs a low-frequency axial vibration drilling tool handle with adjustable amplitude and connected with the machine tool by standard connection mode. The design principle of the frequency rotation ratio of the vibration drilling tool handle is obtained, the working principle and amplitude adjustment mode of the tool handle are analyzed, and the theoretical vibration curve of the tool handle is calculated by analyzing the chip-breaking mechanism of vibration drilling. The actual amplitude and axial output characteristics of the tool handle were tested, thereby guiding the further application of vibration drilling.
It is a significant challenge for microrobots to achieve fast crawling speed at the millimeter scale due to the limitation of actuator size effects. In this letter, we have designed a ...millimeter-scale microrobot configuration based on a new electric pulse drive principle. The microrobot has a high resonant frequency by utilizing Joual Heat generated from the pulsed electric arc. This vibrational excitation causes friction between the robot's legs and the ground to drive a fast-crawling movement. The microrobot can crawl forward on a smooth glass surface at a speed of up to 66.3 body lengths per second. It is also possible to move forward on a rough sandpaper surface at the maximum speed of up to 39.3 body lengths per second. The robot's millimeter size, fast crawling speed, and environmental adaptability enable it to operate in a wide range of future detection and reconnaissance applications.
A macro–micro dual-drive positioning system was developed for Scanning Beam Interference Lithography (SBIL) which uses a dual-frequency laser interferometer as the position reference and exhibits the ...characteristics of long travel, heavy load, and high accuracy. The macro-motion system adopts a friction-driven structure and a feedforward PID control algorithm, and the stroke can reach 1800 mm. The micro-motion system adopts a flexible hinge–plus-PZT driving method and a PID control algorithm based on neural networks, which achieves sufficient positioning accuracy of this system at the nanometer level. An optical-path-sealing system was used to reduce the measurement noise of the dual-frequency laser interferometer. The static stability of the positioning system, the stepping capacity of the macro-motion system, the stepping capacity of the micro-motion system, and the positioning accuracy of the system were tested and analyzed. Additionally, the sources and effects of errors during the motion process were assessed in detail. Finally, the experimental results show that the workbench can locate at the nanoscale within the full range of travel, which can satisfy the SBIL exposure requirement.
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