Actuators

17 pages, 2410 KiB

Open AccessArticle

AILC for Rigid-Flexible Coupled Manipulator System in Three-Dimensional Space with Time-Varying Disturbances and Input Constraints

by Jiaming Zhang, Xisheng Dai, Qingnan Huang and Qiqi Wu

Actuators 2022, 11(9), 268; https://doi.org/10.3390/act11090268 - 19 Sep 2022

Cited by 3 | Viewed by 2007

Abstract

In this paper, an adaptive iterative learning control (AILC) law is developed for two-link rigid-flexible coupled manipulator system in three-dimensional (3D) space with time-varying disturbances and input constraints. Based on the Hamilton’s principle, a dynamic model of a manipulator system is established. The [...] Read more.

In this paper, an adaptive iterative learning control (AILC) law is developed for two-link rigid-flexible coupled manipulator system in three-dimensional (3D) space with time-varying disturbances and input constraints. Based on the Hamilton’s principle, a dynamic model of a manipulator system is established. The conditional equation that is coupled by ordinary differential equations and partial differential equations is derived. In order to achieve high-precision tracking of the revolving angles and vibration suppression of the elastic part, the iterative learning control law based on the disturbance observer is considered in the process of the design controller. The composite Lyapunov energy function is proposed to prove that the angle errors and elastic deformation can eventually converge to zero with the increase of the number of iterations. Ultimately, the simulation results to rigid-flexible coupled manipulator system are given to prove the convergence of the control objectives under the adaptive iterative learning control law. Full article

(This article belongs to the Special Issue Intelligent Control of Flexible Manipulator Systems and Robotics)

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15 pages, 11535 KiB

Open AccessArticle

PMSM Adaptive Sliding Mode Controller Based on Improved Linear Dead Time Compensation

by Huipeng Chen, Zhiqiang Yao, Yongqing Liu, Jian Lin, Peng Wang, Jian Gao, Shaopeng Zhu and Rougang Zhou

Actuators 2022, 11(9), 267; https://doi.org/10.3390/act11090267 - 19 Sep 2022

Cited by 3 | Viewed by 2082

Abstract

Aiming at the issue of the sliding mode observer (SMO) being sensitive to the motor model parameters at low speeds, a rotor position observation method based on resistance adaptive SMO and considering the influence of inverter dead time is designed in this paper. [...] Read more.

Aiming at the issue of the sliding mode observer (SMO) being sensitive to the motor model parameters at low speeds, a rotor position observation method based on resistance adaptive SMO and considering the influence of inverter dead time is designed in this paper. In this method, the online resistance identification is introduced into the conventional SMO, the resistance parameters of the SMO are modified in real-time, and the online resistance identification algorithm is designed by using the Lyapunov function. An enhanced linear dead time compensation method is proposed to improve the resistance adaptive SMO and eliminate the voltage error between the estimated and the actual motor models in order to address the impact of inverter dead time on the voltage parameters in the estimation model at low speeds. Simulation results show that the online resistance identification and dead time compensation can significantly improve the accuracy of sensorless speed control at low speeds, and the dead time compensation can also improve the accuracy of online resistance identification. Full article

(This article belongs to the Section Control Systems)

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16 pages, 10257 KiB

Open AccessArticle

A Backstepping Controller Based on a Model-Assisted Extended State Observer for a Slice Rotor Supported by Active Magnetic Bearings

by Boyuan Xu, Jin Zhou and Longxiang Xu

Actuators 2022, 11(9), 266; https://doi.org/10.3390/act11090266 - 13 Sep 2022

Viewed by 1941

Abstract

To improve the robustness of a slice rotor system supported by active magnetic bearings (AMBs), here, we propose a backstepping controller based on a model-assisted extended state observer (MESO-BC). Based on a generalized extended state observer (GESO), a model-assisted extended state observer is [...] Read more.

To improve the robustness of a slice rotor system supported by active magnetic bearings (AMBs), here, we propose a backstepping controller based on a model-assisted extended state observer (MESO-BC). Based on a generalized extended state observer (GESO), a model-assisted extended state observer is studied with consideration of the linear model of AMBs. The model-assisted extended state observer can estimate the unknown disturbances of the active magnetic bearing system, such as model inaccuracy and external disturbance, and is superior to the generalized extended state observer with respect to observation errors and the speed of convergence errors. In addition, it is compared with the backstepping controller based on a generalized extended state observer (GESO-BC) and conventional adaptive backstepping controller (ABC), and the simulation and experimental results verify the effectiveness of the proposed method. The experimental results demonstrate that the overshoot of the MESO-BC decrease by 5.94% and 13.2% as compared with the GESO-BC and ABC under the effect of pulse disturbance, respectively, and the rotor displacement of the MESO-BC reduce by 40.3% and 54.6% as compared with the GESO-BC and ABC under the effect of the sinusoidal disturbance, respectively. Full article

(This article belongs to the Section Control Systems)

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18 pages, 8169 KiB

Open AccessArticle

Composite Sliding Mode Control of High Precision Electromechanical Actuator Considering Friction Nonlinearity

by Bangsheng Fu, Hui Qi, Jiangtao Xu and Ya Yang

Actuators 2022, 11(9), 265; https://doi.org/10.3390/act11090265 - 13 Sep 2022

Cited by 1 | Viewed by 2188

Abstract

Friction nonlinearity, which is common in electromechanical actuator (EMA) systems, leads to undesired dynamic responses such as “flat top”, low-speed crawl, which brings challenges to high precision attitude control of flight vehicles. In order to improve the robustness of the actuator control system [...] Read more.

Friction nonlinearity, which is common in electromechanical actuator (EMA) systems, leads to undesired dynamic responses such as “flat top”, low-speed crawl, which brings challenges to high precision attitude control of flight vehicles. In order to improve the robustness of the actuator control system under friction nonlinearity, and suppress the chattering caused by high gain of sliding mode control (SMC), a composite SMC scheme based on modified extended state observer (MESO) is proposed. Nonlinear MESO is adopted for estimating the nonlinear friction dynamics, unmodeled disturbance, and external real-time load dynamics so as to compensate for their adverse effect. At the same time, in order to improve the robustness of EMA, and reduce the tracking error of the servo system, SMC is adopted to ensure the tracking error convergence in a finite time. The stability of the proposed method is proved, and the effectiveness is verified by simulations. Full article

(This article belongs to the Section Control Systems)

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26 pages, 7871 KiB

Open AccessArticle

Double Redundancy Electro-Hydrostatic Actuator Fault Diagnosis Method Based on Progressive Fault Diagnosis Method

by Hai-Tao Qi, Dong-Ao Zhao, Duo Liu and Xu Liu

Actuators 2022, 11(9), 264; https://doi.org/10.3390/act11090264 - 13 Sep 2022

Cited by 8 | Viewed by 3197

Abstract

The electro-hydrostatic actuator (EHA) is the key component of most electric aircraft, and research on its fault diagnosis technology is of great significance to improve the safety and reliability of aircraft flight. However, traditional fault diagnosis methods only focus on partial failures and [...] Read more.

The electro-hydrostatic actuator (EHA) is the key component of most electric aircraft, and research on its fault diagnosis technology is of great significance to improve the safety and reliability of aircraft flight. However, traditional fault diagnosis methods only focus on partial failures and cannot completely diagnose the whole EHA system. In this paper, the progressive fault diagnosis method (PFDM) is proposed for overall diagnosis of whole EHA system, which can be divided into four levels for health detection and fault diagnosis of the overall EHA system. PFDM combines fault diagnosis methods based on Kalman filter, threshold, logic, and EHA system analysis model to diagnose the whole EHA system layer by layer. At the same time, in order to ensure the normal operation of the EHA system after fault diagnosis, double redundancy design is creatively carried out for the EHA system to facilitate system reconstruction after fault detection. It can be continuously modified according to different EHA system parameters and measured signals to improve the accuracy of fault diagnosis. The experimental results show that PFDM can accurately locate and identify 22 faults of the double redundancy EHA system by using the accurate EHA system mathematical model. PFDM improves the fault diagnosis response time to 4 ms, greatly improving the safety and reliability of the double redundancy EHA system. Full article

(This article belongs to the Special Issue Advanced Actuators for Aerospace Systems)

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17 pages, 2571 KiB

Open AccessArticle

Design and Optimization of an Active Leveling System Actuator for Lunar Lander Application

by Raffaele Manca, Marco Puliti, Salvatore Circosta, Renato Galluzzi, Sergio Salvatore and Nicola Amati

Actuators 2022, 11(9), 263; https://doi.org/10.3390/act11090263 - 13 Sep 2022

Cited by 2 | Viewed by 2866

Abstract

This work proposes a systematic methodology for designing an active leveling system (ALS) actuator for lunar landing application. The ALS actuator is integrated into an inverted tripod leg layout, exploiting a honeycomb crushable damper as a shock absorber. The proposed ALS actuator is [...] Read more.

This work proposes a systematic methodology for designing an active leveling system (ALS) actuator for lunar landing application. The ALS actuator is integrated into an inverted tripod leg layout, exploiting a honeycomb crushable damper as a shock absorber. The proposed ALS actuator is fitted within the leg’s primary strut and features a custom permanent-magnet synchronous machine rigidly coupled with a lead screw. The actuator aims to both provide proper leg deployment functioning and compensate for the different shock absorber deformations during landing. The leg dynamic behavior is simulated through a parameterized multi-body model to investigate different landing scenarios. First, a parametric sensitivity approach is used to optimize the transmission system and the electric machine characteristics. Then, the electric motor model is numerically validated and optimized through electromagnetic finite element analysis. To validate the proposed ALS design methodology, a virtual test bench is used to assess the ALS performances under different load scenarios. It is found that the proposed methodology is able to yield a compact, well-sized actuator which is numerically validated with the EL3 platform as a case study. Full article

(This article belongs to the Special Issue Aerospace Mechanisms and Actuation)

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17 pages, 5969 KiB

Open AccessArticle

Design of a 2T1R-Type Parallel Mechanism: Performance Analysis and Size Optimization

by Dongbao Wang, Jing Zhang, Hongwei Guo, Rongqiang Liu and Ziming Kou

Actuators 2022, 11(9), 262; https://doi.org/10.3390/act11090262 - 11 Sep 2022

Cited by 6 | Viewed by 2047

Abstract

The planar three-degree-of-freedom (DoF) parallel mechanism plays a significant role in the fields of automobiles and electronics due to its advantages such as high stiffness, large carrying capability, and stable operation. In this paper, a planar 3-DoF (2T1R) parallel mechanism is derived by [...] Read more.

The planar three-degree-of-freedom (DoF) parallel mechanism plays a significant role in the fields of automobiles and electronics due to its advantages such as high stiffness, large carrying capability, and stable operation. In this paper, a planar 3-DoF (2T1R) parallel mechanism is derived by structural evolution from the parallelogram by means of Grassmann line geometry and the Atlas method. First, the position equation of the mechanism is established and the inverse kinematics and Jacobian matrix are investigated. The maximum deviation between the theory and simulation results of the inverse kinematics and Jacobian matrix is 0.48%, which verifies the accuracy of the theoretical model. Then, the constraint conditions of the mechanism are defined. Based on the inverse position solution, the numerical method is used to solve the workspace of the mechanism. It is concluded that the ratio of the workspace to the entire triangular space is about 15% higher than that of the 3-PRR parallel mechanism. Next, based on the Jacobian matrix, the performance indexes are established to evaluate stiffness and dexterity. Finally, the size of the mechanism is optimized by means of the genetic algorithm to improve the comprehensive performance. Full article

(This article belongs to the Section Actuators for Robotics)

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13 pages, 2823 KiB

Open AccessArticle

Electromechanical Natural Frequency Analysis of an Eco-Friendly Active Sandwich Plate

by Rasool Moradi-Dastjerdi and Kamran Behdinan

Actuators 2022, 11(9), 261; https://doi.org/10.3390/act11090261 - 9 Sep 2022

Cited by 5 | Viewed by 2014

Abstract

In conventional piezoelectric ceramics, their brittle nature and containing lead are two crucial issues that significantly restrict their uses in many applications such as biomedical devices. In this work, we suggest the use of an eco-friendly piezoelectric nanocomposite material to piezoelectrically activate a [...] Read more.

In conventional piezoelectric ceramics, their brittle nature and containing lead are two crucial issues that significantly restrict their uses in many applications such as biomedical devices. In this work, we suggest the use of an eco-friendly piezoelectric nanocomposite material to piezoelectrically activate a cantilever meta-structure plate to be used as a novel actuator/sensor or even energy harvester; this cantilever plate is formed of several polymeric links to create an auxetic core plate that structurally shows a negative Poisson’s ratio. Moreover, the active nanocomposite materials are used as the face sheets on the auxetic plate; these active layers are made of nanowires of zinc oxide (ZnO) that are placed into an epoxy matrix in different forms of functionally graded (FG) patterns. For such active sandwich plates (ASPs) with potential electromechanical applications, a coupled electromechanical analysis has been performed to numerically investigate their natural frequencies as a crucial design parameter in such electromechanical devices. By developing a meshless method based on a higher plate theory, the effects of nanowire volume fraction, nanowire distribution, auxetic parameters, layer dimensions, and electrical terminal set-up have been studied; this in-depth study reveals that ASPs with an auxetic core have much lower natural frequencies than ASPs with honeycomb cores which would be very helpful in designing actuators or energy harvesters using the proposed cantilever sandwich plates. Full article

(This article belongs to the Special Issue Multifunctional Active Materials and Structures Based Actuators)

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23 pages, 45965 KiB

Open AccessArticle

Numerical Analysis of Energy Recovery of Hybrid Loader Actuators Based on Parameters Optimization

by Hongyun Mu, Yanlei Luo, Yu Luo and Lunjun Chen

Actuators 2022, 11(9), 260; https://doi.org/10.3390/act11090260 - 8 Sep 2022

Cited by 5 | Viewed by 2169

Abstract

The conventional loader actuator hydraulic system suffers from the potential energy waste problem of the boom arm. This study proposes a hydraulic control method and control strategy for the energy recovery and regeneration of a hybrid loader arm. When the boom arm drops, [...] Read more.

The conventional loader actuator hydraulic system suffers from the potential energy waste problem of the boom arm. This study proposes a hydraulic control method and control strategy for the energy recovery and regeneration of a hybrid loader arm. When the boom arm drops, the piston side of the boom cylinder charges the accumulator, and the system achieves energy recovery. When the boom arm rises, the accumulator releases hydraulic energy to drive the energy regeneration hydraulic motor to provide energy for the system, and the system achieves energy regeneration. The system’s principle analysis and the mathematical model are completed based on Boyle’s, Newton’s second law, and the flow continuity principle. The simulation model is established using AMESim 2D mechanical library, HCD library, and signal library. Under the typical working condition, 50-type wheel loader numerical simulation research is conducted, and the system cylinder motion characteristics, accumulator charging and discharging performance, system energy recovery, and regeneration performance are obtained. On this basis, energy recovery and regeneration efficiency are selected as optimization objectives. The optimal designs of accumulator and energy regeneration hydraulic motor parameters are carried out to obtain the influence law of accumulator and hydraulic motor parameters on system energy recovery and regeneration, and the energy-saving effect of the system is analyzed. The results show that the optimized parameters effectively improve the system energy recovery and regeneration efficiency and reduce engine fuel consumption. The system provides a reference for designing an energy recovery system and researching the energy-saving technology of loaders. Full article

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17 pages, 3113 KiB

Open AccessArticle

A Novel High-Speed Third-Order Sliding Mode Observer for Fault-Tolerant Control Problem of Robot Manipulators

by Van-Cuong Nguyen, Xuan-Toa Tran and Hee-Jun Kang

Actuators 2022, 11(9), 259; https://doi.org/10.3390/act11090259 - 8 Sep 2022

Cited by 8 | Viewed by 2540

Abstract

In this paper, a novel fault-tolerant control tactic for robot manipulator systems using only position measurements is proposed. The proposed algorithm is constructed based on a combination of a nonsingular fast terminal sliding mode control (NFTSMC) and a novel high-speed third-order sliding mode [...] Read more.

In this paper, a novel fault-tolerant control tactic for robot manipulator systems using only position measurements is proposed. The proposed algorithm is constructed based on a combination of a nonsingular fast terminal sliding mode control (NFTSMC) and a novel high-speed third-order sliding mode observer (TOSMO). In the first step, the high-speed TOSMO is proposed for the first time to approximate both the system velocity and the lumped unknown input with a faster convergence time compared to the TOSMO. The faster convergence speed is obtained thanks to the linear characteristic of the added elements. In the second step, the NFTSMC is designed based on a nonsingular fast terminal sliding (NFTS) surface and the information obtained from the proposed high-speed TOSMO. Thanks to the combination, the proposed controller–observer tactic provides excellent features, such as a fast convergence time, high tracking precision, chattering phenomenon reduction, robustness against the effects of the lumped unknown input and velocity requirement elimination. Especially, the proposed observer does not only improve the convergence speed of the estimated signals, but also increases the system dynamic response. The system’s finite-time stability is proved using the Lyapunov theory. Finally, to validate the efficiency of the proposed strategy, simulations on a PUMA560 robot manipulator are performed. Full article

(This article belongs to the Special Issue 10th Anniversary of Actuators)

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17 pages, 2762 KiB

Open AccessArticle

Fast Terminal Sliding Mode Control Based on Finite-Time Observer and Improved Reaching Law for Aerial Robots

by Pu Yang, Kejia Feng, Yu Ding and Ziwei Shen

Actuators 2022, 11(9), 258; https://doi.org/10.3390/act11090258 - 8 Sep 2022

Cited by 5 | Viewed by 1641

Abstract

In this paper, a non-singular fast terminal sliding mode control (NFTSMC) strategy based on a finite-time observer and improved reaching rate is proposed to solve the control problem of aerial robot systems subject to actuator faults and internal and external disturbances. Using the [...] Read more.

In this paper, a non-singular fast terminal sliding mode control (NFTSMC) strategy based on a finite-time observer and improved reaching rate is proposed to solve the control problem of aerial robot systems subject to actuator faults and internal and external disturbances. Using the control strategy proposed in this paper, rapid convergence and high robustness of the system are guaranteed. In addition, the proposed finite-time observer can observe information related to the actuator fault or internal and external disturbance of the system in an accurate and timely fashion, and actively compensate the fault. The improved reaching law introduced in this paper can cause the system reach the sliding surface quickly, effectively improving the response speed of the system and increasing the tracking performance of the system. The stability of the whole system is proved using Lyapunov stability analysis. Finally, the effectiveness of the proposed control strategy is verified on the basis of a numerical simulation of a six-rotor UAV model with manipulator. Full article

(This article belongs to the Section Aircraft Actuators)

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15 pages, 2720 KiB

Open AccessArticle

Research on Performance Evaluation Method of Rice Thresher Based on Neural Network

by Qiang Da, Dexin Li, Xiaolei Zhang, Weiling Guo, Dongyu He, Yanfei Huang and Gengchao He

Actuators 2022, 11(9), 257; https://doi.org/10.3390/act11090257 - 8 Sep 2022

Cited by 9 | Viewed by 2448

Abstract

Because the threshing device of a combine harvester determines the harvesting level and threshing separation performance of a combine harvester, the analysis and study of the threshing device of a combine harvester is key to improving its performance. Based on the threshing device [...] Read more.

Because the threshing device of a combine harvester determines the harvesting level and threshing separation performance of a combine harvester, the analysis and study of the threshing device of a combine harvester is key to improving its performance. Based on the threshing device of a half-feed combine harvester, the simulation model of a discrete element threshing device is established in this paper. With the threshing drum rotation speed, feed volume, and concave sieve vibration frequency as the variable factors, the BP neural network model and linear regression equation model established for the loss rate and impurity content for two kinds of threshing performance indicators, respectively, and through the discrete element threshing performance test, two kinds of methods of threshing performance prediction are analyzed. The results show that the neural network and linear regression can be used for the threshing performance indicators, however, the BP neural network prediction effect has a better prediction precision, better reliability, and the trained neural network can be used in the general case of the threshing performance indicators. This provides a new idea for improving the threshing performance of a combine harvester. Full article

(This article belongs to the Special Issue Recent Advances and Challenges in Agricultural Robotics, Unmanned Agricultural Machinery and Autonomous Farming Technologies)

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10 pages, 6733 KiB

Open AccessArticle

A Hybrid Control Strategy for a PMSM-Based Aircraft Cargo Door Actuator

by Xin Wang, Xiaolu Wang, Zhao Xue, Peng Guo and Shuai Liu

Actuators 2022, 11(9), 256; https://doi.org/10.3390/act11090256 - 8 Sep 2022

Viewed by 2940

Abstract

There are some disadvantages of a traditional AC-induced motor or hydraulic cylinder-based aircraft cargo door actuator (CDA), such as strong stopping shock, big slippage, high power, or current demand. To solve these problems, a permanent magnet synchronous motor (PMSM)-based linear CDA has been [...] Read more.

There are some disadvantages of a traditional AC-induced motor or hydraulic cylinder-based aircraft cargo door actuator (CDA), such as strong stopping shock, big slippage, high power, or current demand. To solve these problems, a permanent magnet synchronous motor (PMSM)-based linear CDA has been developed, and a hybrid control method combining speed plan and control, power current restriction has been proposed. In other words, low-speed-loop servo control is used in opening and closing positions, and power restricted control is adopted otherwise. A multidisciplinary model is constructed with Simulink. The simulation results show that vibration and slippage are reduced dramatically for the cargo door mechanism, and power is restricted during the whole procedure, which also results in good adaptability performance over a wide range of loads and temperatures. Experiments with different load levels on a test rig and in a temperature chamber at −50 °C are implemented to verify the effectiveness of the strategy. Full article

(This article belongs to the Special Issue Aerospace Mechanisms and Actuation)

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22 pages, 2117 KiB

Open AccessArticle

Neural Adaptive Robust Motion-Tracking Control for Robotic Manipulator Systems

by Daniel Galvan-Perez, Hugo Yañez-Badillo, Francisco Beltran-Carbajal, Ivan Rivas-Cambero, Antonio Favela-Contreras and Ruben Tapia-Olvera

Actuators 2022, 11(9), 255; https://doi.org/10.3390/act11090255 - 7 Sep 2022

Cited by 7 | Viewed by 2899

Abstract

This paper deals with the motion trajectory tracking control problem based on output feedback and artificial neural networks for anthropomorphic manipulator robots under disturbed operating scenarios. This class of manipulator robots constitutes nonlinear dynamic systems subjected to disturbance torques induced mainly by work [...] Read more.

This paper deals with the motion trajectory tracking control problem based on output feedback and artificial neural networks for anthropomorphic manipulator robots under disturbed operating scenarios. This class of manipulator robots constitutes nonlinear dynamic systems subjected to disturbance torques induced mainly by work payload. Parametric uncertainty and possible dynamic modeling errors stand for other kind of disturbances that can deteriorate the efficiency and robustness of the tracking of controlled nonlinear robotic system trajectories. In fact, the presence of unknown dynamic disturbances is unavoidable in industrial robotic engineering systems. Therefore, for high-precision applications, such as laser cutting, marking, or welding, effective control schemes should be designed to guarantee adequate motion profile tracking planned on this class of disturbed nonlinear robotic system. In this context, a new adaptive robust motion trajectory tracking control scheme based on output feedback and artificial neural networks of anthropomorphic manipulator robots is presented. Three-layer B-spline artificial neural networks and time-series modeling are properly exploited in the design of novel adaptive robust motion tracking controllers for robotic applications of laser manufacturing. In this way, dependency on detailed nonlinear mathematical modeling of robotic systems is considerably reduced, and real-time estimation of uncertain dynamic disturbances is not required. Furthermore, several cases studies to demonstrate the motion planning tracking control robustness for a class of MIMO nonlinear robotic systems are described. blue Insights for the extension of the introduced output-feedback adaptive neural control design approach for other architecture of nonlinear robotic systems are depicted. Full article

(This article belongs to the Special Issue Actuators for Identification, Vibration Analysis, and Control of Mechatronic Systems)

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20 pages, 10147 KiB

Open AccessArticle

Design and Experimental Tests of a Buoyancy Change Module for Autonomous Underwater Vehicles

by J. Falcão Carneiro, J. Bravo Pinto, F. Gomes de Almeida and N. A. Cruz

Actuators 2022, 11(9), 254; https://doi.org/10.3390/act11090254 - 4 Sep 2022

Cited by 4 | Viewed by 2700

Abstract

Ocean exploration is of major importance for several reasons, including energy and mineral resource retrieval, sovereignty, and environmental concerns. The use of autonomous underwater vehicles (AUV) has thus been receiving increased attention from the scientific community. In this context, it has been shown [...] Read more.

Ocean exploration is of major importance for several reasons, including energy and mineral resource retrieval, sovereignty, and environmental concerns. The use of autonomous underwater vehicles (AUV) has thus been receiving increased attention from the scientific community. In this context, it has been shown that the use of buoyancy change modules (BCMs) can significantly improve the energy efficiency of an AUV. However, the literature regarding the detailed design of these modules is scarce. This paper contributes to this field by describing the development of an electromechanical buoyancy change module prototype to be incorporated into an existing AUV. A detailed description of the constraints and compromises existing in the design of the device components is presented. In addition, the mechanical design of the hull based on FEM simulations is described in detail. The prototype is experimentally tested in a shallow pool where its full functionality is shown. The paper also presents preliminary experimental values of the power consumption of the device and compares them with the ones provided by existing models in the literature. Full article

(This article belongs to the Section Control Systems)

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14 pages, 2289 KiB

Open AccessArticle

Robotic Knee Prosthesis with Cycloidal Gear and Four-Bar Mechanism Optimized Using Particle Swarm Algorithm

by Mouaz Al Kouzbary, Hamza Al Kouzbary, Jingjing Liu, Taha Khamis, Zaina Al-Hashimi, Hanie Nadia Shasmin, Nooranida Arifin and Noor Azuan Abu Osman

Actuators 2022, 11(9), 253; https://doi.org/10.3390/act11090253 - 1 Sep 2022

Cited by 3 | Viewed by 3053

Abstract

A powered transfemoral prosthesis is needed as people with transfemoral amputation show 60 percent extra metabolic cost when compared to people with no amputation. Recently, as illustrated in the literature, the most high-torque robotic knee prosthesis utilize harmonic reducers. Despite the advantage of [...] Read more.

A powered transfemoral prosthesis is needed as people with transfemoral amputation show 60 percent extra metabolic cost when compared to people with no amputation. Recently, as illustrated in the literature, the most high-torque robotic knee prosthesis utilize harmonic reducers. Despite the advantage of high reduction ratio and efficiency, the harmonic drive cannot be back-driven. Therefore, the harmonic drive is not an optimal solution for prosthetic systems with direct and indirect contact with the environment. In this paper, we outline an initial design of robotic knee prosthesis. The proposed robotic knee prosthesis consists of BLDC motor, cycloidal gear with reduction ratio 13:1, four-bar mechanism, and timing belt transmission with 4:1 reduction ratio. To optimize the torque transmission and range of motion (RoM), a multiobjective optimization problem must be undertaken. The end-effector motion depends on each bar length in the four-bar mechanism. The four-bar mechanism was optimized using particle swarm optimization (PSO). To complete the optimization, a set of 50 steps was collected using wearable sensors. Then, the data of sagittal plan were processed to identify the target profile for PSO. The prototype’s computer-aided manufacturing (CAM) was completed using a MarkTwo 3D printer with carbon fiber composite. The overall design can achieve a maximum torque of 84 N.m. However, the current design lacks the elastic component (no spring is added on the actuator output), which is necessary for a functional prosthesis; this limitation will be addressed in future study. Full article

(This article belongs to the Special Issue Soft Exoskeleton and Supernumerary Limbs for Human Augmentation)

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19 pages, 3702 KiB

Open AccessArticle

Design and Testing of Accurate Dicing Control System for Fruits and Vegetables

by Song Mei, Fengque Pei, Zhiyu Song and Yifei Tong

Actuators 2022, 11(9), 252; https://doi.org/10.3390/act11090252 - 1 Sep 2022

Cited by 3 | Viewed by 2630

Abstract

It is hard to control the dicing size of current fresh-cutting devices for fruits and vegetables precisely, and this can be influenced by complex working environments. This paper looks at traditional three-dimensional fresh-cutting machines and, apart from analyzing the force-and-motion equation to determine [...] Read more.

It is hard to control the dicing size of current fresh-cutting devices for fruits and vegetables precisely, and this can be influenced by complex working environments. This paper looks at traditional three-dimensional fresh-cutting machines and, apart from analyzing the force-and-motion equation to determine the minimum rotational speed of the roller, the cross-cutting tool’s independent drive system, the speed detection system of the material before dicing, and shaft-speed monitoring have also been analyzed in order to develop precise control technology for three-dimensional fruit and vegetable dicing by considering dicing input-speed detection and by fine-tuning the cross-cutting tool’s dicing speed. Performance tests are carried out on the prototype before and after improvement. The results show that when the size of carrots and potatoes was 11 mm × 10 mm × 10 mm and 11 mm × 10 mm × 12 mm, the slice thickness and strip thickness error before improvement were 20% and 5%, respectively. Due to the structural limitations, the slice error was large, but the strip error as ideal. The dicing error was greater than 15% due to the different damping coefficients of the materials and the variable speed movement. After the adjustment, the overall dicing error was less than 10%, and the accuracy and stability were higher. Full article

(This article belongs to the Special Issue Designing, Sensing, Instrumentation, Diagnosis, Controlling, and Integration of Actuators in Digital Manufacturing Especially in Aerospace Engineering)

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16 pages, 3547 KiB

Open AccessArticle

Second-Order Model-Based Predictive Control of Dual Three-Phase PMSM Based on Current Loop Operation Optimization

by Long Li, Weidong Zhou, Xianting Bi, Xuetao Sun and Xiaoping Shi

Actuators 2022, 11(9), 251; https://doi.org/10.3390/act11090251 - 1 Sep 2022

Cited by 4 | Viewed by 1745

Abstract

To reduce the amount of computation in traditional model predictive current control, to improve the flexibility in choosing the direction and amplitude in the voltage vector synthesis of a dual three-phase motor by two degrees of freedom, and to reduce the output torque [...] Read more.

To reduce the amount of computation in traditional model predictive current control, to improve the flexibility in choosing the direction and amplitude in the voltage vector synthesis of a dual three-phase motor by two degrees of freedom, and to reduce the output torque ripple and current ripple, this paper proposes a dual second-order model predictive control algorithm based on current loop operation optimization. Compared with the conventional speed loop using the PI control algorithm and the traditional MPC control algorithm, the proposed algorithm adopts the second-order MPC control mode in the speed loop, which decreases the speed regulation time and increases motor immunity. Meanwhile, the second-order MPC control mode is adopted in the current loop, and the traditional iterative calculation method is improved to calculate the direction and amplitude of the output voltage vector through the analytic function, which increases the flexibility of the output voltage vector. Additionally, a four-vector SVPWM is employed to modulate the voltage vector to reduce the current amplitude in the harmonic subspace. The simulation results indicate that the algorithm proposed in this paper can significantly reduce the torque ripple and the current ripple as well as increase the transient performance of the motor. Full article

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11 pages, 2289 KiB

Open AccessArticle

A Novel Self-Actuated Linear Drive for Long-Range-of-Motion Electromechanical Systems

by Mason Dooley and Xiangrong Shen

Actuators 2022, 11(9), 250; https://doi.org/10.3390/act11090250 - 1 Sep 2022

Cited by 1 | Viewed by 4212

Abstract

Obtaining powered linear movement over a long range of motion is a common yet challenging task, as the majority of linear actuators have limited ranges of motion as determined by their functioning mechanisms. In this paper, the authors present a novel belt-based self-actuated [...] Read more.

Obtaining powered linear movement over a long range of motion is a common yet challenging task, as the majority of linear actuators have limited ranges of motion as determined by their functioning mechanisms. In this paper, the authors present a novel belt-based self-actuated linear drive (B-SALD), in which a self-powered moving platform slides on a slotted track with essentially unlimited range of motion (only limited by the length of the track). Unlike the traditional rack-and-pinion mechanism, the B-SALD system uses a double-sided timing belt as the power-transmitting element. With the teeth on its inner surface, the belt interacts with a timing pulley for its own circulation; with the teeth on its outer surface, the belt interacts with a linear rail with parallel slots and drives the translation of the moving platform. The unique functioning mechanism generates multiple distinct advantages: no lubrication is required; the slotted track is simple and inexpensive to manufacture; and it provides an inherent compliance to buffer shock loading. With the experiments conducted on a preliminary prototype, it has been demonstrated that the B-SALD is able to provide accurate positioning and continuous motion control, an overall mechanical efficiency of 70% over the majority of the load range, and the capability of generating large force output in the desired manner. Full article

(This article belongs to the Section Precision Actuators)

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10 pages, 2640 KiB

Open AccessArticle

3D Printed Device for Separation of Cells and Particles by Tilted Bulk Acoustic Wave Actuation

by Adem Ozcelik

Actuators 2022, 11(9), 249; https://doi.org/10.3390/act11090249 - 31 Aug 2022

Cited by 8 | Viewed by 2280

Abstract

Three-dimensional (3D) printing has been proven to be a reliable manufacturing method for a diverse set of applications in engineering. Simple benchtop tools such as mini centrifuges, automated syringe pumps, and basic-robotic platforms have been successfully printed by basic 3D printers. The field [...] Read more.

Three-dimensional (3D) printing has been proven to be a reliable manufacturing method for a diverse set of applications in engineering. Simple benchtop tools such as mini centrifuges, automated syringe pumps, and basic-robotic platforms have been successfully printed by basic 3D printers. The field of lab-on-a-chip offers promising functions and convenience for point-of-care diagnostics and rapid disease screening for limited resource settings. In this work, stereolithography (SLA) 3D resin printing is implemented to fabricate a microfluidic device to be used for separation of HeLa cells from smaller polystyrene particles through titled angle standing bulk acoustic wave actuation. The demonstrated device achieved continuous and efficient separation of target cells with over 92% HeLa cell purity and 88% cell recovery rates. Overall, 3D printing is shown to be a viable method for fabrication of microfluidic devices for lab-on-a-chip applications. Full article

(This article belongs to the Section Miniaturized and Micro Actuators)

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17 pages, 4528 KiB

Open AccessArticle

A Rotary-Linear Ultrasonic Motor Using MnO₂-Doped (Ba_0.97Ca_0.03)(Ti_0.96Sn_0.005Hf_0.035)O₃ Lead-Free Piezoelectric Ceramics with Improved Curie Temperature and Temperature Stability

by Cheng-Che Tsai, Sheng-Yuan Chu, Wei-Hsiang Chao and Cheng-Shong Hong

Actuators 2022, 11(9), 248; https://doi.org/10.3390/act11090248 - 31 Aug 2022

Cited by 2 | Viewed by 2088

Abstract

In this work, a cylindrical lead-free rotary-linear ultrasonic motor was attached to piezoelectric plates of MnO₂-doped (Ba_0.97Ca_0.03)(Ti_0.96Sn_0.005Hf_0.035)O₃ ceramics using the first bending vibration to pull a thread output shaft of [...] Read more.

In this work, a cylindrical lead-free rotary-linear ultrasonic motor was attached to piezoelectric plates of MnO₂-doped (Ba_0.97Ca_0.03)(Ti_0.96Sn_0.005Hf_0.035)O₃ ceramics using the first bending vibration to pull a thread output shaft of the interior of a stator. The effect of the proposed ceramics’ d₃₃ and Q_m values are the key factors for ultrasonic motors. Therefore, MnO₂-doped (Ba_0.97Ca_0.03)(Ti_0.96Sn_0.005Hf_0.035)O₃ lead-free piezoelectric ceramics with high values of d₃₃ = 230 pC/N, Q_m = 340.8 and a good temperature stability of their dielectric and piezoelectric properties are suitable for application to linear piezoelectric motors. The structure of the linear piezoelectric motor was simulated and fabricated by Finite Element Analysis. The characteristics of linear piezoelectric motors were also studied. The output characteristics of the lead-free piezoelectric motor were a left-pull velocity = 3.21 mm/s, a right-pull velocity = 3.39 mm/s, an up-pull velocity = 2.56 mm/s and a force >2 N at 39.09 kHz for an input voltage of approximately 200 V_p-p (peak to peak). These results are comparable to those for a lead-based piezoelectric motor that uses PZT-4 ceramics. The proposed lead-free piezoelectric motors were successfully fabricated and used to pull a 0.5 mL commercial insulin syringe. Full article

(This article belongs to the Special Issue Piezoelectric Actuators—A Special Issue in Honor of Prof. Dr. Kenji Uchino)

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14 pages, 2157 KiB

Open AccessArticle

Toward the Trajectory Predictor for Automatic Train Operation System Using CNN–LSTM Network

by Yijuan He, Jidong Lv, Hongjie Liu and Tao Tang

Actuators 2022, 11(9), 247; https://doi.org/10.3390/act11090247 - 31 Aug 2022

Cited by 10 | Viewed by 2405

Abstract

The accurate trajectory of the train ahead with more dynamic behaviour, such as train position, speed, acceleration, etc., is the critical issue of virtual coupling for future railways, which can drastically reduce their headways and increase line capacity. This paper presents an integrated [...] Read more.

The accurate trajectory of the train ahead with more dynamic behaviour, such as train position, speed, acceleration, etc., is the critical issue of virtual coupling for future railways, which can drastically reduce their headways and increase line capacity. This paper presents an integrated convolutional neural network (CNN) and long short-term memory (LSTM) hybrid model for the task of trajectory prediction. A CNN–LSTM hybrid algorithm has been proposed. The model employs CNN and LSTM to extract the spatial dimension feature of the trajectory and the long-term dependencies of train trajectory data, respectively. The proposed CNN–LSTM model has superiority in achieving collaborative data mining on spatiotemporal measurement data to simultaneously learn spatial and temporal features from phasor measurement unit data. Therefore, the high-precision prediction of the train trajectory prediction is achieved based on the sufficient fusion of the above features. We use real automatic train operation (ATO) collected data for experiments and compare the proposed method with recurrent neural networks (RNN), recurrent neural networks (GRU), LSTM, and stateful-LSTM models on the same data sets. Experimental results show that the prediction performance of long-term trajectories is satisfyingly accurate. The root mean square error (RMSE) error can be reduced to less than 0.21 m, and the hit rate achieves 93% when the time horizon increases to 4S, respectively. Full article

(This article belongs to the Special Issue Advancing Actuators-Based Land Transport Systems: State of the Art and New Technologies)

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14 pages, 5006 KiB

Open AccessArticle

A Soft Pneumatic Gripper with Endoskeletons Resisting Out-of-Plane Bending

by Hongjun Li, Dengyu Xie and Yeping Xie

Actuators 2022, 11(9), 246; https://doi.org/10.3390/act11090246 - 31 Aug 2022

Cited by 14 | Viewed by 3598

Abstract

The established soft pneumatic grippers have the benefit of flexible and compliant gripping, but they cannot withstand lateral loads, due to the low stiffness of soft material. This paper proposes an endoskeleton gripper. The soft action of the finger is performed by air [...] Read more.

The established soft pneumatic grippers have the benefit of flexible and compliant gripping, but they cannot withstand lateral loads, due to the low stiffness of soft material. This paper proposes an endoskeleton gripper. The soft action of the finger is performed by air chambers, and the gripping force is transferred by the rigid endoskeleton within the finger. The endoskeleton in the finger is similar to a wristwatch chain; the hinge mechanism permits relative rotation in the working plane but restricts out-of-plane bending, greatly increasing the finger stiffness. The endoskeleton and gripper holder can be 3D-printed with CR-PLA material. The finger was fabricated by molding of silicone gel. The gripper can perform enveloping grasping and pinch grasping operations depending on the object size, weight, and surrounding environment. The finger bending and gripper grasping performance were investigated by experiments and finite element analysis. The fingertip force of the endoskeleton gripper was about 1.45 times higher than that of the gripper without endoskeleton. It was found that the gripper can grasp objects with a maximum diameter of 80.5 mm and a weight of 450 g, which were 80.5% of the finger length and six times the finger self-weight, respectively. Full article

(This article belongs to the Section Actuators for Robotics)

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20 pages, 14282 KiB

Open AccessArticle

Lightweight Dual-Mode Soft Actuator Fabricated from Bellows and Foam Material

by Zhiwei Jiao, Zhongyu Zhuang, Yue Cheng, Xuan Deng, Ce Sun, Yuan Yu and Fangjun Li

Actuators 2022, 11(9), 245; https://doi.org/10.3390/act11090245 - 30 Aug 2022

Cited by 6 | Viewed by 3225

Abstract

Foam-based soft actuators are lightweight and highly compressible, which make them an attractive option for soft robotics. A negative pressure drive would complement the advantages of foam actuators and improve the durability of the soft robotic system. In this study, a foam actuator [...] Read more.

Foam-based soft actuators are lightweight and highly compressible, which make them an attractive option for soft robotics. A negative pressure drive would complement the advantages of foam actuators and improve the durability of the soft robotic system. In this study, a foam actuator was designed with a negative pressure pneumatic drive comprising bellows air chambers, a polyurethane foam body, and sealing layers at the head and tail. Experiments were performed to test the bending and contraction performances of the actuator with the foaming multiplier and air chamber length as variables. At air pressures of 0–90 kPa, the bending angle and contraction of the actuator increased with the foaming multiplier and number of air chamber sections. The designed actuator achieved a bending angle of 56.2° and contraction distance of 34 mm (47.9% of the total length) at 90 kPa, and the bending and contraction output forces were 3.5 and 7.2 N, respectively. A control system was built, and four soft robots were constructed with different numbers of actuators. In experiments, the robots successfully completed operations such as lifting, gripping, walking, and gesturing. The designed actuator is potentially applicable to debris capture, field rescue, and teaching in classrooms. Full article

(This article belongs to the Section Actuators for Robotics)

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21 pages, 2504 KiB

Open AccessArticle

Lateral Stability Analysis of 4WID Electric Vehicle Based on Sliding Mode Control and Optimal Distribution Torque Strategy

by Hongwei Wang, Jie Han and Haotian Zhang

Actuators 2022, 11(9), 244; https://doi.org/10.3390/act11090244 - 26 Aug 2022

Cited by 14 | Viewed by 2376

Abstract

In this paper, we propose a lateral stability control strategy for four-wheel independent drive (4WID) electric vehicles. The control strategy adopts a hierarchical structure. First, a seven-degree-of-freedom (7DOF) 4WID electric vehicle model is established. Then, the upper controller adopts the integral sliding mode [...] Read more.

In this paper, we propose a lateral stability control strategy for four-wheel independent drive (4WID) electric vehicles. The control strategy adopts a hierarchical structure. First, a seven-degree-of-freedom (7DOF) 4WID electric vehicle model is established. Then, the upper controller adopts the integral sliding mode control (ISMC) method to obtain the desired yaw moment by controlling both the yaw rate and the sideslip angle. A new sliding mode reaching law (NSMRL) is designed to reduce chattering and make state variables converge faster, and the superiority of NSMRL is verified by theoretical analysis. The lower controller proposes a new optimal allocation algorithm, which selects the tire utilization rate and the standard deviation coefficient of the tire utilization rate as the objective function. The safety performance of vehicle is improved, and the instability caused by the significant difference in the stability margin between the four wheels under extreme road conditions is avoided. Finally, a simulation is carried out to verify the effectiveness of the proposed control strategy under single-lane-change and J-turn maneuvers. Full article

(This article belongs to the Section Actuators for Land Transport)

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16 pages, 2362 KiB

Open AccessArticle

A Novel Radially Closable Tubular Origami Structure (RC-ori) for Valves

by Siyuan Ye, Pengyuan Zhao, Yinjun Zhao, Fatemeh Kavousi, Huijuan Feng and Guangbo Hao

Actuators 2022, 11(9), 243; https://doi.org/10.3390/act11090243 - 26 Aug 2022

Cited by 13 | Viewed by 4687

Abstract

Cylindrical Kresling origami structures are often used in engineering fields due to their axial stretchability, tunable stiffness, and bistability, while their radial closability is rarely mentioned to date. This feature enables a valvelike function, which inspired this study to develop a new origami-based [...] Read more.

Cylindrical Kresling origami structures are often used in engineering fields due to their axial stretchability, tunable stiffness, and bistability, while their radial closability is rarely mentioned to date. This feature enables a valvelike function, which inspired this study to develop a new origami-based valve. With the unique one-piece structure of origami, the valve requires fewer parts, which can improve its tightness and reduce the cleaning process. These advantages meet the requirements of sanitary valves used in industries such as the pharmaceutical industry. This paper summarizes the geometric definition of the Kresling pattern as developed in previous studies and reveals the similarity of its twisting motion to the widely utilized iris valves. Through this analogy, the Kresling structure’s closability and geometric conditions are characterized. To facilitate the operation of the valve, we optimize the existing structure and create a new crease pattern, RC-ori. This novel design enables an entirely closed state without twisting. In addition, a simplified modeling method is proposed in this paper for the non-rigid foldable cylindrical origami. The relationship between the open area and the unfolded length of the RC-ori structure is explored based on the modeling method with a comparison with nonlinear FEA simulations. Not only limited to valves, the new crease pattern could also be applied to microreactors, drug carriers, samplers, and foldable furniture. Full article

(This article belongs to the Special Issue Mechanism Design and Control for Robotics)

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13 pages, 3514 KiB

Open AccessArticle

Fabrication and Actuation Performance of Selective Laser Melting Additive-Manufactured Active Shape-Memory Alloy Honeycomb Arrays

by Yuesheng Xu, Lei Qiu and Shenfang Yuan

Actuators 2022, 11(9), 242; https://doi.org/10.3390/act11090242 - 24 Aug 2022

Cited by 5 | Viewed by 2071

Abstract

Shape-memory alloy (SMA) honeycomb arrays have drawn worldwide attention for their potential active applications in smart morphing wings. However, the manufacturing of complex active SMA honeycomb arrays via conventional processes is a difficult task, and the actuation performance of the honeycomb arrays has [...] Read more.

Shape-memory alloy (SMA) honeycomb arrays have drawn worldwide attention for their potential active applications in smart morphing wings. However, the manufacturing of complex active SMA honeycomb arrays via conventional processes is a difficult task, and the actuation performance of the honeycomb arrays has not yet been well–investigated. In this work, the active SMA honeycomb arrays were fabricated by selective laser melting (SLM) additive manufacturing, and their actuation performance was investigated. The results show that the SLM–fabricated active SMA honeycomb arrays can generate obvious actuation performance during the transformation and exhibit a higher maximum actuation stress of 2.53 MPa at a R/t ratio of 4 and a tensile pre–strain of 35%. This research will contribute to the design and further improvement of active SMA honeycomb arrays based on SLM additive manufacturing, promoting the engineering applications for smart morphing wings. Full article

(This article belongs to the Special Issue Shape Memory Alloys and Piezoelectric Materials and Their Applications)

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Actuators, Volume 11, Issue 9 (September 2022) – 27 articles

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