Maximum Rotational Speed Research Articles

Impact of wind turbine operation conditions on infrasonic and low frequency sound induced by on-shore wind turbines

In this paper, the influence of wind turbine operation conditions, like rotational speed, nacelle position and output power, on the low- and infrasonic sound emissions at the wind farm and sound immissions at residential buildings will be investigated. For this purpose, parallel measurements were carried out at a wind farm on the Swabian Alb in complex terrain and at four residential locations in the vicinity of the wind farm over a period of two months. Distinctive tones can be assigned to the blade passage at different rotational speeds. Furthermore, tones at 28.9 Hz (rated) and 18.3 Hz (below rated) with two higher harmonics can be attributed to the wind turbine generator. Wind farm infrasonic tones at the blade passing frequency were detected at the wind farm and residential buildings. At the residential buildings infrasonic tones were detected mainly for maximum rotational speed of the wind turbines and seem to be independent from wind direction.

A novel 3-DoF piezoelectric robotic pectoral fin: design, simulation, and experimental investigation

The fish pectoral fins, which play a vital role for fish swimming mobility, can perform three degree-of-freedom movements (rowing, feathering, and flapping motions), promoting that a lot of bionic robotic pectoral fins have been proposed and developed. However, these developed robotic pectoral fins driven by electromagnetic motors or smart materials still cannot fully realize the aforementioned three movement modes. To solve this problem, a novel piezoelectric robotic pectoral fin based on the converse piezoelectric effect and friction drive principle is proposed in this study, to achieve the three motion modes. Using a piezoelectric actuator, the robotic pectoral fin can be driven to move with three degree-of-freedom motion modes. Firstly, the overall structures of the proposed piezoelectric robotic pectoral fin and the designed piezoelectric actuator are explained in detailed. Additionally, a finite element simulation and a combination of vibration measurement and impedance analysis experiments are carried out to verify the effectiveness of the proposed piezoelectric actuator. Finally, an experimental investigation is conducted to evaluate output performances of the robotic pectoral fin prototype. Experimental results indicated that (a) the maximum average velocities of the rowing and flapping motions of the pectoral fin prototype under an excitation voltage of 550 Vpp are 290 and 241.7 deg s−1, respectively, and the maximum rotation speed of the feathering motion is 6.03 deg s−1; (b) the maximum output forces of the rowing and flapping motions of the pectoral fin are 2.156 and 2.107 N, respectively; (c) rowing motion start stop response times are 13 and 10.6 ms, flapping motion start and stop response times are 14.2 and 9.2 ms, and feathering motion start/stop response times are 34 and 56.8 ms, respectively.

Cross-talk elimination for lenslet array near eye display based on eye-gaze tracking.

Lenslet array (LA) near-eye displays (NEDs) are a recent technical development that creates a virtual image in the field of view of one or both eyes. A problem occurs when the user's pupil moves out of the LA-NED eye box (i.e., cross-talk) making the image look doubled or ghosted. It negatively impacts the user experience. Although eye-gaze tracking can mitigate this problem, the effect of the solution has not been studied to understand the impact of pupil size and human perception. In this paper, we redefine the cross-talk region as the practical pupil movable region (PPMR50), which differs from eye box size because it considers pupil size and human visual perception. To evaluate the effect of eye-gaze tracking on subjective image quality, three user studies were conducted. From the results, PPMR50 was found to be consistent with human perception, and cross-talk elimination via eye-gaze tracking was better understood in a static gaze scenario. Although the system latency prevented the complete elimination of cross-talk for fast movements or large pupil changes, the problem was greatly alleviated. We also analyzed system delays based on PPMR50, which we newly defined in this paper and provided an optimization scheme to meet the maximum eyeball rotation speed.

High durability variable geometry turbine for commercial vehicle turbochargers

Abstract Transportation sector constitutes a major portion in the Green House Gas (GHG) emissions of the world. Reduction of GHG emission requires the development of highly efficient Internal Combustion Engines (ICE) which are downsized using turbochargers that provide compressed air for cleaner combustion. Variable Geometry (VG) turbochargers are widely accepted for this application because of the ability of VG turbine to function at wider flow range. This ensures the supply of compressed air at low engine speeds also. However, the interaction between stator vanes and turbine rotor has been a major issue in terms of High Cycle Fatigue (HCF) of such a turbocharger. Till now, a conservative design approach constrained the maximum rotation speed to below resonance speed for vibration mode 2. But, to achieve further downsizing it would be necessary to challenge higher rotation speeds. This paper will firstly introduce the tip-timing experiment and CFD-FEA simulations used to evaluate the HCF of VG turbine, and secondly it discusses the results of new VG turbine system which achieved safe operability even at vibration mode 3, both on simulation and experiment. The tip-timing experiment was conducted at 680°C on hot gas stand test bench with optical sensors installed circumferentially around the rotor tip. These measurements have been verified and validated with the safety factor calculated from blade surface pressure data obtained from transient rotor CFD simulations.

Experimental investigation of transient thermal characteristics of a dry friction clutch using alternative friction materials under different operating conditions

AbstractThe thermal characteristics of four types of dry friction clutch materials (LUK, G95, HCC, and Tiger) are investigated experimentally and numerically in the present work under different working conditions; such as initial sliding angular velocity (ωro), torque (T), and sliding time (ts). The temperature distributions over a cross‐section of friction clutch elements (pressure plate and flywheel) are investigated and optimized during the sliding period (heating phase), and full engagement period (cooling phase). The effect of alternative frictional materials lining of a clutch disc on the thermal behavior of the sliding system under different operating conditions (different angular velocities, torques, and sliding periods) is investigated experimentally. The results showed that the maximum effect on the temperature values occurred when applying maximum torque (4.5 kg·m), maximum initial rotational speed (1200 rpm), slipping period (30 s). However, the temperature values at interface contact decrease when decreasing all the above input conditions values to (2.5 kg·m, 690 rpm, and slipping period to 8 s). The results showed that the temperature reduced (53%) from (180.4°C) for applied torque 4.5 kg·m with initial rotational speed (1200 rpm) and slip period (30 s) to (83.3°C) when applied torque 2.5 kg·m, initial rotational speed (680 rpm) and slip period (8 s) for clutch disc (LUK). It was obtained the same behavior for the other three discs (G95, HCC, and Tiger), but with different values of temperatures. The results show that the temperatures of the pressure plate interface (Tmax = 159.1°C) are higher than those at the flywheel interface (Tmax = 152.7°C), due to the low thermal capacity of pressure plate compared to the flywheel when using G95 frictional material. The experimental optimization results showed that the highest temperatures were obtained when using friction clutch disc (LUK), and minimum temperature when using (HCC) disc, around (20%) reduction when replaced (LUK) material with (HCC) under the same working conditions (T = 4.5 kg·m, ωro = 1200 rpm, and ts = 30 s).

Experimental investigation of defect formation, microstructure and mechanical properties in friction stir welding of AA5086

The joint conditions of a weldment entirely rely on the set of process parameters applied during the welding operation. In friction stir welding (FSW), proper mechanical mixing of the material signifies the appropriate welding variables. The present work aspires to investigate the influence of tool rotational speed (RS), welding speed (WS) and plunge depth (PD) on external as well as internal defect formation, identify the different types of defect encountered during the FSW process, and evaluate the influence of different parameters on tensile properties and microstructure of the joints. In order to achieve the goal of the present work, a detailed experimental investigation was carried out using AA5086-O as base metal. On account of high strength-to-weight ratio, good weldability and high corrosion resistance, friction stir welded joints of aluminum alloys are widely applications in aerospace, automotive, railway and shipbuilding industry. It has been observed that theultimate tensile strength (UTS) of joint tends to decrease when there is increased in the welding speed at constant PD of 0.2 mm and RS of 1400 rpm. Similarly, with consistent PD of 0.3 mm and rotational speed of 2000 rpm, UTS of joints initially enhanced with an increment in welding speed and then reduced eventually. A joint fabricated with maximum rotation speed, intermediate welding speed and the higher plunge depth produced highest tensile strength of 215 MPa which is 16% higher than the conditions required for aerospace applications of FSW for aluminum alloys, as per the standard of American Welding Society (AWS). Microscopic analysis was conducted to scientifically ascertain the grain size, crystal structure and surface morphology of the FSW joints.

CFD simulation of hydrodynamics characteristics in a tank with forward-reverse rotating impeller

BackgroundA forward-reverse rotating impeller was used in an unbaffled tank to improve the mixing efficiency. Flow field and power characteristics in the tank were numerically studied. MethodsComputational fluid dynamics(CFD) simulations were performed to investigate hydrodynamics in the unbaffled tank. The Reynolds stress turbulence (RST) model along with a sliding mesh approach was used to predict instantaneous flow fields in the stirred tank. Significant findingsFluid in the unbaffled tank flows periodically with the forward-reverse impeller agitation. Zonal flow phenomenon was found for the fluid affected by agitation in different directions. The effects of operating conditions on instantaneous fluid velocity vary with positions in the tank. Flow field characteristics in the forward-reverse agitated unbaffled tank are very different from those in constant agitated unbaffled and baffled tanks. Generally, transient power consumption is only the function of its corresponding transient rotational speed. The averaged impeller power number is a constant and is not affected by maximum rotational speed and cycle time. The averaged power number is the largest in the unbaffled tank with forward-reverse agitation, followed by the baffled tank at a constant agitation, and the smallest in the unbaffled tank at a constant impeller speed.

Design and simulation of 5kW BLDC motor with half-buried permanent magnets using an existing stator body

<span lang="EN-US">This paper proposes a design of a 5 kW, 100 volts brushless direct current (DC) (BLDC) motor using an existing stator connected to an inverter and equipped with Hall sensors. The stator is a radial flux motor-type with 54 slots positioned at the outer side of the machine. In this case, the design is focused on the rotor components and winding configuration. However, the inverter aspects are also taken into account. At the same time, it considers the expected outputs: voltage, power, speed; and some limitations: maximum current and flux density. Finite element magnetic-based simulation is performed to extract the magnetic flux distribution, and analytical calculations are then conducted to obtain the output values and characteristics. The results show the BLDC motor at nominal speed produces 5.1 kW output power with 122.34 V voltages, 97.09% efficiency, and torque of 32.82 Nm. The maximum torque and rotation speeds are 51.39 Nm and 4,150 rpm respectively, while the peak-to-peak cogging force is 1.35 Nm. It can be concluded that the BLDC motor has a good performance and is compatible with the connected inverter.</span>

Wind Tunnel Experiments on Interaction between Two Closely Spaced Vertical-Axis Wind Turbines in Side-by-Side Arrangement

This study aimed to determine the optimal rotor spacing of two vertical-axis wind turbines, which are simulated by miniature models arranged side-by-side with a relatively low aspect ratio. Wind tunnel experiments with a pair of 3-D printed model rotors were conducted at a uniform velocity. A series of experiments were conducted involving both incremental adjustments to the rotor gaps, g, and the rotational direction of each rotor. Increases in the power and the related flow patterns were observed in all three arrangements: Co-Rotating (CO), Counter-Up (CU), and Counter-Down (CD). The maximum phase-synchronized rotational speed occurs at the narrowest gap in the CD arrangement. Meanwhile, local maxima arise in the CO and CU arrangements at g/D < 1, where D is the rotor diameter. From an engineering perspective, the optimal rotor spacing is g/D = 0.2 with the CO arrangement, using the same two rotors rotating in the same direction. Based on flow visualization using a smoke-wire method at a narrower gap opening of 0.2D, the wake width in the case of the CU arrangement was remarkably narrower than those obtained in the CO and CD arrangements. In the CU arrangement, a movement towards the center of the rotor pair of the nominal front-stagnation point of each rotor was confirmed via flow visualization. This finding explains a reduction tendency in the rotational speed of the rotors via a reduction in the lift in the CU arrangement.

Experimental Investigation of Aerostatic Journal Bearings Made of Carbon Fiber-Reinforced Carbon Composites

Abstract This study describes experimental results using carbon fiber-reinforced carbon (C/C) material for porous journal bearings under static conditions. Exerted radial forces of up to 90 N, a supply pressure of up to 6 bar, and a maximum rotational speed of 8000 rpm were tested. The occurrence of pneumatic hammering was not observed under these operating points. Triangulation sensors were mounted vertically and horizontally as well as in front of and behind the tested bearing. These sensors measure the eccentricity and misalignment. The orbit analysis demonstrated an improvement in concentricity with an increment in the supply pressure. The layered structure of the C/C material used for the porous liner is presented. A rotational speed below 8000 rpm negligibly influenced the load-carrying capacity and the flowrate. The vertical misalignment of the shaft was determined in relation to the force-applied test bearing. In addition, two vertically positioned sensors on the support-bearing housing were used to discern the misalignment in the absolute system. On the other hand, reducing the speed to 1000 rpm increased the concentricity error. The shaft showed no significant signs of use after the experiments. The measurements confirm the suitability of the material for porous bearings.

Raising the Speed Limit of Axial Piston Pumps by Optimizing the Suction Duct

The maximum delivery pressure and the maximum rotational speed determine the power density of axial piston pumps. However, increasing the speed beyond the limit always accompanies cavitation, leading to the decrease of the volumetric efficiency. The pressure loss in the suction duct is considered a significant reason for the cavitation. Therefore, this paper proposes a methodology to optimize the shape of the suction duct aiming at reducing the intensity of cavitation and increasing the speed limit. At first, a computational fluid dynamics (CFD) model based on the full cavitation model (FCM) is developed to simulate the fluid field of the axial piston pump and a test rig is set to validate the model. Then the topology optimization is conducted for obtaining the minimum pressure loss in the suction duct. Comparing the original suction duct with the optimized one in the simulation model, the pressure loss in the suction duct gets considerable reduction, which eases the cavitation intensity a lot. The simulation results prove that the speed limit can increase under several different inlet pressures.

Hierarchically Structured and Scalable Artificial Muscles for Smart Textiles.

Fiber-based artificial muscles with excellent actuation performance are gaining great attention as soft materials for flexible actuators; however, current advances in fiber-based artificial muscles generally suffer from high cost, harsh stimulation regimes, limiting deformations, chemical toxicity, or complex manufacturing processing, which hinder the widespread application of those artificial muscles in engineering and practical usage. Herein, a facile cross-scale processing strategy is presented to construct commercially available nontoxic viscose fibers into fast responsive and humidity-driven yarn artificial muscles with a recorded torsional stroke of 1752° cm-1 and a maximum rotation speed up to 2100 rpm, which are comparable to certain artificial muscles made from carbon-based composite materials. The underlying mechanism of such outstanding actuation performance that begins to form at a mesoscale is discussed by theoretical modeling and microstructure characterization. The as-prepared yarn artificial muscles are further scaled up to large-sized fabric muscles through topological weaving structures by integrating different textile technologies. These fabric muscles extend the simple motion of yarn muscles into higher-level diverse deformations without any composite system, complex synthetic processing, and component design, which enables the development of new fiber-based artificial muscles for versatile applications, such as smart textiles and intelligent systems.

Materials Selection and Design Options Analysis for a Centrifugal Fan Impeller in a Horizontal Conveyor Dryer.

Comparative strength analysis of two popular options of the radial centrifugal fan impeller design used in horizontal conveyor dryer for fine-grained raw materials is presented. Three types of materials for impeller manufacturing—ASTM A36 steel, Hardox 450 steel and aluminium alloy 6061-T6 are considered. The finite element method (FEM) has been used to investigate stresses and deformations of the impeller within the operational speed range. Analysis shows that the better design is the impeller made of Hardox 450 steel with a central disk. Although the maximum stress is slightly higher in the blades slot for central disk fitting for this design option, it has greatly reduced stresses in contact edges with two other disks (by 22–38%) and blades bending deformation (by 51%). For this design, the maximum operational rotation speed is 1135 min according to the yield strength with a 15% safety factor, while for basic design, it is 1225 min. The rational choice of material depends on maximum value of the yield stress to density ratio as well as taking into account the operating conditions and required fan performance. Recommendations for manufacturing the centrifugal fan impeller related to chosen material are given.

Design and Manufacturing Method of GFRP Blades for Vertical Axis Wind Turbine

Today, environmental protection and the rational use of natural resources have become growing challenges. One of these aspects is energy producing with less impact on the environment. For some applications the small wind turbines can be a solution. In this paper are presented some aspects regarding the design and manufacturing technology of 500 W vertical axis wind turbine blades. The turbine will be installed in the urban environment so that requirements regarding rotor aesthetics and noise level will be considered. The optimal geometric parameters of the turbine rotor were determined by specialized MathCAD and elaborated in 3D modelling software. For the blades the NACA 0018 airfoil was used with the chord length of 110 mm and is constant throughout the length of the blade. The blades are helical and are 1800 mm long. To estimate the aerodynamic performance of the turbine rotor, a computational fluid dynamics model was developed using ANSYS CFX finite element analysis software. The authors proposed a new method for rapid prototyping of blades using fused deposition modelling procedure. In order to increase the mechanical properties, the blades were covered with several layers of glass-fibres reinforced polymer. Estimation the blade strength to operating loads was performed using Ansys Workbench software. The modelling of the composite material architecture on the blade surface was performed using the special ANSYS Composite PrepPost module. Several simulations were performed with different number of layers and stacking sequences. In order to prevent rotor over engineering the maximum rotation speed of 400 min−1 was accepted (equivalent to ≍12 m/s wind speed). Simulation of the blade strength to operating loads indicate values of around 40 MPa for shear stress (50% less than failure shear stress) and around 80 MPa principal stress (60% less than failure tensile stress). The maximum blade deformations of 3 – 4 mm shows that the blade is stiff enough at imposed operation conditions. For the blade manufacturing, based on the numerical analysis results, the configuration of the strength structure composed of 5 layers of GFRP was selected, which forms a total blade weight of 1895g.

Parametric analysis on a simple design water reaction turbine for low-head low-flow Pico-hydro generation system

This paper presents a parametric analysis of the outward flow reaction type turbine known as a Z-Blade turbine for low-head low-flow conditions. By applying the principles of mass conservation, momentum and energy, a nomogram was designed to investigate the theoretical performance characteristics. Based on the parametric analysis and the governing equations and experimental results, attempts have been made to prove that the mass flow rate, angular speed, centrifugal head, power output and efficiency respond dynamically to the water head, radius of the rotor, size of the PVC pipes and the nozzle exit area. A turbine with a 1” pipe diameter gives a higher performance compared to a 1/2” pipe diameter, and certainly the performances of both pipe sizes are improved when the supplied potential energy is increased. This innovative turbine has a maximum rotational speed at an optimum turbine diameter at 0.6m, accompanied by a point where there is a sudden reduction in the water flow rate, where previously the increment in the water flow rate was very high. This can shows from the outcome nomogram with 1” pipe diameter can perform 350 rpm speed with 1.48 L/sec water flow. The Z-Blade turbine has been examined and has shown good potential to be used for low-head (3m, 4m and 5m) and low-flow (less than 2.5 L/sec) conditions.

Positioning, transfer, and rotation movements of particles manipulated by a novel piezoelectric acoustofluidic device with multiple vibration modes

Acoustic-based manipulation platforms are the preferred device to manipulate particles in analytical chemistry and biomedicine due to their label-free and high biocompatibility. As a significant wave mode of the acoustic manipulation method, bulk acoustic waves (BAWs) have been wildly concerned by academia and industry. To realize the high-precise multi-mode manipulation of particles with a simple structure, a BAWs-based piezoelectric acoustofluidic device is proposed. It is composed of a Langevin transducer and a disk with a circular groove. Two vibration modes of the disk with three and five node circles, respectively, are used to manipulate particles to position, transfer, and rotate. A non-nodal acoustic trap is induced in the disk center by producing its first out-of-plane bending vibration mode. In this acoustic trap, the spherical particles and irregularly shaped particles can be fixed entirely and rotated, respectively. Simultaneously, the disk center is an antinode of the acoustic field induced by the second disk out-of-plane bending vibration mode, leading to that the trapped particles can be equidistantly transferred from the disk center to the nearest node. The effectiveness of the proposed device is verified by simulations and experiments. With appropriate control parameters, the minimum position fluctuation of the submillimeter-hollow-glass sphere (SHGS) after being positioned is 0.32% of its diameter. Moreover, the maximum transfer speed of the SHGS and maximum rotation speed of the cylindrical metal wire are 130.8 mm s−1 and 23.51 rad s−1, respectively. This proposed device is capable of multiple manipulation modes for particles with simple control strategy, providing a novel method for designing a BAWs-based device to achieve the manipulation of particles.

Dynamic characteristics analysis for energy release process of liquid air energy storage system

In order to further research the dynamic characteristics of liquid air energy storage (LAES) system under typical operating conditions, a dynamic simulation model of energy release process of the 10 MW LAES system is established in this paper. The characteristic curves of expander are considered during modeling and simulation process. The dynamic changes of key parameters, such as temperature, pressure, mass flow rate, and so on, of energy storage system over time under the startup and grid connection are simulated. The sensitivity analyses of rotor speed rising rate and frequency disturbance on the key parameters are carried out. The results show that the outlet temperature and outlet pressure of 1st expander stabilized at 395.96K and 5.37 MPa, respectively, at 602s when the rotor starts up with a rising rate of 360 rpm/min. The actual rotor speed reaches the maximum value of 3010r/min at 504s, the overspeed ratio is 100.3%. During the grid connection, the outlet temperature and outlet pressure of 1st expander stabilized at 345.6K and 3.0 MPa, respectively, at 910s, and the mass flow rate of air rises from 11.25 kg/s of the no-load operation to 23.60 kg/s. In addition, the rotor speed rising rate and frequency disturbance have great influence on the key parameters of expander. The new startup scheme of changing rotor speed rising rate have been put forward to balance the relationship between maximum rotor speed and startup time. The fluctuation amplitudes of outlet temperature, outlet pressure, power and rotor speed increase with the frequency disturbance amplitude increasing. The analysis results of dynamic simulation can provide data reference for learning the dynamic characteristics of LAES system.

The time-dependent distribution of optical polarization angle changes in blazars

ABSTRACT At optical wavelengths, blazar Electric Vector Position Angle (EVPA) rotations linked with gamma-ray activity have been the subject of intense interest and systematic investigation for over a decade. One difficulty in the interpretation of EVPA rotations is the inherent 180° ambiguity in the measurements. It is therefore essential, when studying EVPA rotations, to ensure that the typical time-interval between successive observations – i.e. the cadence – is short enough to ensure that the correct modulo 180° value is selected. This optimal cadence depends on the maximum intrinsic EVPA rotation speed in blazars, which is currently not known. In this paper, we address the following questions for the RoboPol sample: What range of rotation speeds for rotations greater than 90° can we expect? What observation cadence is required to detect such rotations? Have rapid rotations been missed in EVPA rotation studies thus far? What fraction of data is affected by the ambiguity? And how likely are detected rotations affected by the ambiguity? We answer these questions with three seasons of optical polarimetric observations of a statistical sample of blazars sampled weekly with the RoboPol instrument and an additional season with daily observations. We model the distribution of EVPA changes on time-scales from 1–30 d and estimate the fraction of changes exceeding 90°. We show that at least daily observations are necessary to measure ${\gt}96{{\ \rm per\ cent}}$ of optical EVPA variability in the RoboPol sample of blazars correctly and that intraday observations are needed to measure the fastest rotations that have been seen thus far.

Fast ATP-Dependent Subunit Rotation in Reconstituted FoF1-ATP Synthase Trapped in Solution.

FoF1-ATP synthases are ubiquitous membrane-bound, rotary motor enzymes that can catalyze ATP synthesis and hydrolysis. Their enzyme kinetics are controlled by internal subunit rotation, by substrate and product concentrations, and by mechanical inhibitory mechanisms but also by the electrochemical potential of protons across the membrane. Single-molecule Förster resonance energy transfer (smFRET) has been used to detect subunit rotation within FoF1-ATP synthases embedded in freely diffusing liposomes. We now report that kinetic monitoring of functional rotation can be prolonged from milliseconds to seconds by utilizing an anti-Brownian electrokinetic trap (ABEL trap). These extended observation times allowed us to observe fluctuating rates of functional rotation for individual FoF1-liposomes in solution. Broad distributions of ATP-dependent catalytic rates were revealed. The buildup of an electrochemical potential of protons was confirmed to limit the maximum rate of ATP hydrolysis. In the presence of ionophores or uncouplers, the fastest subunit rotation speeds measured in single reconstituted FoF1-ATP synthases were 180 full rounds per second. This was much faster than measured by biochemical ensemble averaging, but not as fast as the maximum rotational speed reported previously for isolated single F1 complexes uncoupled from the membrane-embedded Fo complex. Further application of ABEL trap measurements should help resolve the mechanistic causes of such fluctuating rates of subunit rotation.

Novel piezoelectric crawling robot with multiple degrees of freedom

Traditional ultrasonic motors can usually produce either linear or rotational motion. Piezoelectrically driven structures with multiple degrees of freedom require two or more ultrasonic motors, and the manufacturing process is associated with some problems related to their complex structure and difficult control. This study proposes a new structure of a multi-degree-of-freedom piezoelectric crawling robot. Four modes are selected as the working modes, and mode superposition is used to produce the linear and rotational motion of the robot. This structure is designed based on a combination of size and topological optimization to adjust the frequency response consistency of the motor. The performance of the motor was tested on surfaces with different roughnesses. Its performance on the desk surface was the best. Its maximum linear speed is 37 mm/s, and its maximum rotational speed is 6.28 rad/s. The performance tests were performed under different loads. The linear motion speed of the motor reached its maximum value at 29.2 kHz, and the rotational motion speed reached its maximum value at 32.1 kHz.