Actuators

17 pages, 6073 KiB

Open AccessArticle

Design and Preliminary Testing of a Magnetic Spring as an Energy-Storing System for Reduced Power Consumption of a Humanoid Arm

by Jhon F. Rodríguez-León, Ilse Cervantes, Eduardo Castillo-Castañeda, Giuseppe Carbone and Daniele Cafolla

Actuators 2021, 10(6), 136; https://doi.org/10.3390/act10060136 - 21 Jun 2021

Cited by 2 | Viewed by 3782

Abstract

The increasing use of robots in the industry, the growing energy prices, and higher environmental awareness have driven research to find new solutions for reducing energy consumption. In additional, in most robotic tasks, energy is used to overcome the forces of gravity, but [...] Read more.

The increasing use of robots in the industry, the growing energy prices, and higher environmental awareness have driven research to find new solutions for reducing energy consumption. In additional, in most robotic tasks, energy is used to overcome the forces of gravity, but in a few industrial applications, the force of gravity is used as a source of energy. For this reason, the use of magnetic springs with actuators may reduce the energy consumption of robots performing trajectories due their high-hardness magnetic properties of energy storage. Accordingly, this paper proposes a magnetic spring configuration as an energy-storing system for a two DoF humanoid arm. Thus, an integration of the magnetic spring system in the robot is described. A control strategy is proposed to enable autonomous use. In this paper, the proposed device is modeled and analyzed with simulations as: mechanical energy consumption and kinetic energy rotational and multibody dynamics. Furthermore, a prototype was manufactured and validated experimentally. A preliminary test to check the interaction between the magnetic spring system with the mechanism and the trajectory performance was carried out. Finally, an energy consumption comparison with and without the magnetic spring is also presented. Full article

(This article belongs to the Special Issue Intelligent Humanoid Mobile Robots)

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16 pages, 2219 KiB

Open AccessArticle

Lateral Stability Control of Four-Wheel-Drive Electric Vehicle Based on Coordinated Control of Torque Distribution and ESP Differential Braking

by Liqing Chen, Zhiqiang Li, Juanjuan Yang and Yu Song

Actuators 2021, 10(6), 135; https://doi.org/10.3390/act10060135 - 18 Jun 2021

Cited by 28 | Viewed by 4683

Abstract

This research focuses on four-wheel-drive electric vehicles. On the basis of the hierarchical coordinated control strategy, the coordinated control system of driving force distribution regulation and differential braking regulation was designed to increase the electric vehicles steering stability under special road working conditions. [...] Read more.

This research focuses on four-wheel-drive electric vehicles. On the basis of the hierarchical coordinated control strategy, the coordinated control system of driving force distribution regulation and differential braking regulation was designed to increase the electric vehicles steering stability under special road working conditions. A seven-degree-of-freedom model of an electric vehicle was established in MATLAB/Simulink, and then a hierarchical coordination control model of the Electronic stability program and dynamic torque distribution control system was established. Adaptive fuzzy control was applied to ESP and, based on the neural network PID control, a torque distribution control system was designed. On the basis of the proposed coordinated control model, a performance simulation and a hardware-in-the-loop test of the control system under the typical working condition of single line shift were carried out. From the final results, it can be seen that the proposed control strategy can greatly improve the safety of the vehicle after serious side slip, increase the stability of the whole vehicle, and effectively increase the vehicle lateral stability. Full article

(This article belongs to the Special Issue Modelling, Control and Condition Monitoring of Actuator-Based Land Transport Systems)

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15 pages, 1042 KiB

Open AccessArticle

Optimized Voltage-Induced Control of Magnetic Domain-Wall Propagation in Hybrid Piezoelectric/Magnetostrictive Devices

by Giancarlo Consolo and Giovanna Valenti

Actuators 2021, 10(6), 134; https://doi.org/10.3390/act10060134 - 17 Jun 2021

Cited by 3 | Viewed by 2207

Abstract

A theory of voltage-induced control of magnetic domain walls propagating along the major axis of a magnetostrictive nanostrip, tightly coupled with a ceramic piezoelectric, is developed in the framework of the Landau–Lifshitz–Gilbert equation. It is assumed that the strains undergone by the piezoelectric [...] Read more.

A theory of voltage-induced control of magnetic domain walls propagating along the major axis of a magnetostrictive nanostrip, tightly coupled with a ceramic piezoelectric, is developed in the framework of the Landau–Lifshitz–Gilbert equation. It is assumed that the strains undergone by the piezoelectric actuator, subject to an electric field generated by a dc bias voltage applied through a couple of lateral electrodes, are fully transferred to the magnetostrictive layer. Taking into account these piezo-induced strains and considering a magnetostrictive linear elastic material belonging to the cubic crystal class, the magnetoelastic field is analytically determined. Therefore, by using the classical traveling-wave formalism, the explicit expressions of the most important features characterizing the two dynamical regimes of domain-wall propagation have been deduced, and their dependence on the electric field strength has been highlighted. Moreover, some strategies to optimize such a voltage-induced control, based on the choice of the ceramic piezoelectric material and the orientation of dielectric poling and electric field with respect to the reference axes, have been proposed. Full article

(This article belongs to the Special Issue New Design and Applications for Magnetoelastic Actuators)

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16 pages, 6264 KiB

Open AccessArticle

Conceptual Design of Electromechanical Actuation Systems for Large-Sized Directional Control Valves

by Tobias Vonderbank and Katharina Schmitz

Actuators 2021, 10(6), 133; https://doi.org/10.3390/act10060133 - 16 Jun 2021

Cited by 1 | Viewed by 3477

Abstract

Increasing performance in modern hydraulics is achieved by a close investigation of possible enhancements of its components. Prior research has pointed out that electromechanical actuators can form suitable alternatives to hydraulically piloted control systems. Since the requirements at these actuation systems depend on [...] Read more.

Increasing performance in modern hydraulics is achieved by a close investigation of possible enhancements of its components. Prior research has pointed out that electromechanical actuators can form suitable alternatives to hydraulically piloted control systems. Since the requirements at these actuation systems depend on the operating conditions of the system, each actuator can be optimized to the respective hydraulic system. Considering that many different conceptual designs are suitable, the phase of conceptual design plays a decisive role during the design process. Therefore, this paper focuses on the process of developing new conceptual designs for electromechanical valve actuation systems using the method of function structures. Aiming to identify special design features, which need to be considered during the design process of electromechanical actuation systems, an exemplary actuator was designed based on the derived function structure. To highlight the potential of function structures for the development of new electromechanical valve actuation systems, two principal concepts, which allow the reduction of the necessary forces, have been developed by extending the function structure. These concepts have been experimentally investigated to identify their advantages and disadvantages. Full article

(This article belongs to the Special Issue Selected Papers from the 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications (IeCAT))

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18 pages, 29788 KiB

Open AccessArticle

A Modified Model Predictive Torque Control with Parameters Robustness Improvement for PMSM of Electric Vehicles

by Siyu Gao, Yanjun Wei, Di Zhang, Hanhong Qi and Yao Wei

Actuators 2021, 10(6), 132; https://doi.org/10.3390/act10060132 - 15 Jun 2021

Cited by 13 | Viewed by 2975

Abstract

Model predictive torque control with duty cycle control (MPTC-DCC) is widely used in motor drive systems because of its low torque ripple and good steady-state performance. However, the selection of the optimal voltage vector and the calculation of the duration are extremely dependent [...] Read more.

Model predictive torque control with duty cycle control (MPTC-DCC) is widely used in motor drive systems because of its low torque ripple and good steady-state performance. However, the selection of the optimal voltage vector and the calculation of the duration are extremely dependent on the accuracy of the motor parameters. In view of this situation, A modified MPTC-DCC is proposed in this paper. According to the variation of error between the measured value and the predicted value, the motor parameters are calculated in real-time. Meanwhile, Model reference adaptive control (MRAC) is adopted in the speed loop to eliminate the disturbance caused by the ripple of real-time update parameters, through which the disturbance caused by parameter mismatch is suppressed effectively. The simulation and experiment are carried out on MATLAB / Simulink software and dSPACE experimental platform, which corroborate the principle analysis and the correctness of the method. Full article

(This article belongs to the Section Control Systems)

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15 pages, 7502 KiB

Open AccessArticle

Evaluation of Switching Power Amplifier Topology for Active Magnetic Bearings

by Kezhen Yang, Yefa Hu, Xinhua Guo, Jian Zhou and Huachun Wu

Actuators 2021, 10(6), 131; https://doi.org/10.3390/act10060131 - 13 Jun 2021

Cited by 8 | Viewed by 3070

Abstract

Active magnetic bearings (AMBs) have led to great progress in the field of rotating machinery due to their many advantages, such as their non-contact and non-lubrication properties. As the key component of an AMB actuator, the switching power amplifier has an important impact [...] Read more.

Active magnetic bearings (AMBs) have led to great progress in the field of rotating machinery due to their many advantages, such as their non-contact and non-lubrication properties. As the key component of an AMB actuator, the switching power amplifier has an important impact on the performance of magnetic bearings and rotating machinery. In this paper, the topologies of switching power amplifiers for AMBs are introduced. The traditional half-bridge topology and two newly proposed topologies—the three-phase-half-bridge and neutralized-sharing-bridge topology—are analyzed and discussed. The volume, current output performance and cost of the power amplifier with different topologies are comprehensively evaluated, providing a theoretical basis and guidance for the selection and design of the topology of switching power amplifiers for AMBs under different conditions. Full article

(This article belongs to the Special Issue Selected Papers from the 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications (IeCAT))

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18 pages, 2136 KiB

Open AccessArticle

A Novel Design of Water-Activated Variable Stiffness Endoscopic Manipulator with Safe Thermal Insulation

by Qian Gao and Zhenglong Sun

Actuators 2021, 10(6), 130; https://doi.org/10.3390/act10060130 - 13 Jun 2021

Cited by 14 | Viewed by 3824

Abstract

In natural orifice transluminal endoscopic surgery (NOTES), an ideal endoscope platform should be flexible and dexterous enough to go through the natural orifices to access the lesion site inside the human body, and meanwhile provide sufficient rigidity to serve as a base for [...] Read more.

In natural orifice transluminal endoscopic surgery (NOTES), an ideal endoscope platform should be flexible and dexterous enough to go through the natural orifices to access the lesion site inside the human body, and meanwhile provide sufficient rigidity to serve as a base for the end-effectors to operate during the surgical tasks. However, the conventional endoscope has limited ability for maintaining high rigidity over the length of the body. This paper presents a novel design of a variable stiffness endoscopic manipulator. By using a new bioplastic named FORMcard, whose stiffness can be thermally adjusted, water at different temperatures is employed to switch the manipulator between rigid mode and flexible mode. A biocompatible microencapsulated phase change material (MEPCM) with latent heat storage properties is adopted as the thermal insulation for better safety. Experiments are conducted to test the concept design, and the validated advantages of our proposed variable stiffness endoscopic manipulator include: shorter mode activation time (25 s), significantly improved stiffness in rigid mode (547.9–926.3 N·cm

^{2}

) and larger stiffness-adjusting ratio (23.9–25.1 times). Full article

(This article belongs to the Special Issue Robot Control in Human-Machine Systems)

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12 pages, 4010 KiB

Open AccessArticle

Polymorphic Phase Transition and Piezoelectric Performance of BaTiO₃-CaSnO₃ Solid Solutions

by Qian Wang, Hong-Ze Yan, Xian Zhao and Chun-Ming Wang

Actuators 2021, 10(6), 129; https://doi.org/10.3390/act10060129 - 13 Jun 2021

Cited by 10 | Viewed by 4676

Abstract

BaTiO₃-based piezoelectric ceramics have attracted considerable attention in recent years due to their tunable phase structures and good piezoelectric properties. In this work, the (1 − x)BaTiO₃₋xCaSnO₃ (0.00 ≤ x ≤ 0.16, abbreviated as BT₋ [...] Read more.

BaTiO₃-based piezoelectric ceramics have attracted considerable attention in recent years due to their tunable phase structures and good piezoelectric properties. In this work, the (1 − x)BaTiO₃₋xCaSnO₃ (0.00 ≤ x ≤ 0.16, abbreviated as BT₋xCS) solid solutions, were prepared by traditional solid-state reaction methods. The phase transitions, microstructure, dielectric, piezoelectric, and ferroelectric properties of BT-xCS have been investigated in detail. The coexistence of rhombohedral, orthorhombic, and tetragonal phases near room temperature, i.e., polymorphic phase transition (PPT), has been confirmed by X-ray diffraction and temperature-dependent dielectric measurements in the compositions range of 0.06 ≤ x ≤ 0.10. The multiphase coexistence near room temperature provides more spontaneous polarization vectors and facilitates the process of polarization rotation and extension by an external electric field, which is conducive to the enhancement of piezoelectric response. Remarkably, the composition of BT-0.08CS exhibits optimized piezoelectric properties with a piezoelectric coefficient d₃₃ of 620 pC/N, electromechanical coupling factors k_p of 58%, k_t of 40%, and a piezoelectric strain coefficient d₃₃* of 950 pm/V. Full article

(This article belongs to the Special Issue Advances in Piezoelectric Actuators 2022)

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22 pages, 1384 KiB

Open AccessArticle

Advancing Motivation Feedforward Control of Permanent Magnetic Linear Oscillating Synchronous Motor for High Tracking Precision

by Zongxia Jiao, Yuan Cao, Liang Yan, Xinglu Li, Lu Zhang and Yang Li

Actuators 2021, 10(6), 128; https://doi.org/10.3390/act10060128 - 10 Jun 2021

Cited by 6 | Viewed by 2683

Abstract

Linear motors have promising application to industrial manufacture because of their direct motion and thrust output. A permanent magnetic linear oscillating synchronous motor (PMLOSM) provides reciprocating motion which can drive a piston pump directly having advantages of high frequency, high reliability, and easy [...] Read more.

Linear motors have promising application to industrial manufacture because of their direct motion and thrust output. A permanent magnetic linear oscillating synchronous motor (PMLOSM) provides reciprocating motion which can drive a piston pump directly having advantages of high frequency, high reliability, and easy commercial manufacture. Hence, researching the tracking performance of PMLOSM is of great importance to realizing its popularization and application. Traditional PI control cannot fulfill the requirement of high tracking precision, and PMLOSM performance has high phase lag because of high control stiffness. In this paper, an advancing motivation feedforward control (AMFC), which is a combination of advancing motivation signal and PI control signal, is proposed to obtain high tracking precision of PMLOSM. The PMLOSM inserted with AMFC can provide accurate trajectory tracking at a high frequency. Compared with single PI control, AMFC can reduce the phase lag from −18 to −2.7 degrees, which shows great promotion of the tracking precision of PMLOSM. In addition, AMFC will promote the application of PMLOSM to other working conditions needing high frequency reciprocating tracking performance and give PMLOSM greater future prospects. Full article

(This article belongs to the Section Control Systems)

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12 pages, 3631 KiB

Open AccessArticle

Modeling and Fabrication of Soft Actuators Based on Fiber-Reinforced Elastomeric Enclosures

by Zhi Chen, Aicheng Zou, Zhantian Qin, Xingguo Han, Tianming Li and Shengkai Liu

Actuators 2021, 10(6), 127; https://doi.org/10.3390/act10060127 - 9 Jun 2021

Cited by 7 | Viewed by 3316

Abstract

Unlike rigid actuators, soft actuators can easily adapt to complex environments. Understanding the relationship between the deformation of soft actuators and external factors such as pressure would enable rapid designs based on specific requirements, such as flexible, compliant endoscopes. An effective model is [...] Read more.

Unlike rigid actuators, soft actuators can easily adapt to complex environments. Understanding the relationship between the deformation of soft actuators and external factors such as pressure would enable rapid designs based on specific requirements, such as flexible, compliant endoscopes. An effective model is demonstrated that predicts the deformation of a soft actuator based on the virtual work principle and the geometrically exact Cosserat rod theory. The deformation process is analyzed for extension, bending, and twisting modules. A new manufacturing method is then introduced. Through any combination of modules, the soft actuator can have a greater workspace and more dexterity. The proposed model was verified for various fiber-reinforced elastomeric enclosures. There is good agreement between the model analysis and the experimental data, which indicates the effectiveness of the model. Full article

(This article belongs to the Special Issue Robot Control in Human-Machine Systems)

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23 pages, 10884 KiB

Open AccessArticle

Flywheel-Based Boom Energy Recovery System for Hydraulic Excavators with Load Sensing System

by Jiansong Li, Yu Han and Shaohui Li

Actuators 2021, 10(6), 126; https://doi.org/10.3390/act10060126 - 9 Jun 2021

Cited by 4 | Viewed by 3232

Abstract

A hydraulic excavator (HE) is a typical piece of construction equipment and is widely used in various construction fields. However, the poor energy efficiency of HEs results in serious energy waste and has aroused the attention of researchers. Furthermore, rising fuel prices and [...] Read more.

A hydraulic excavator (HE) is a typical piece of construction equipment and is widely used in various construction fields. However, the poor energy efficiency of HEs results in serious energy waste and has aroused the attention of researchers. Furthermore, rising fuel prices and increasing stringent waste gas emission legislation sparked demand for ways to improve energy efficiency. Recovering the otherwise wasted boom potential energy of a conventional HE by proper methods offers the potential to improve the fuel efficiency of HEs. In this paper, a mechanical energy recovery system consisting of a pump/motor and a flywheel is presented for HEs using a load sensing system. When the boom moves down, the boom potential energy is converted into mechanical energy by the boom cylinder and the pump/motor to accelerate the flywheel. When needed, the captured energy stored in the flywheel is converted back into a form of pressure energy to directly drive the boom cylinder up without throttling the main valve. In the lifting process, a compound circuit that consists of a throttling control circuit and a displacement control circuit is presented. A control strategy is proposed to optimize the energy recovery and reuse procedure. A 4-t HE is used as a study case to investigate the energy-saving potential of the proposed system. Numeric simulations show that the proposed system, when compared with a conventional load sensing system, can reduce as much as 48.9% energy consumption in a non-loaded cycle of boom lifting and lowering process. As to a fully loaded case, the energy-saving rate is 16.9%. This research indicates the flywheel-based scheme is promising for developing an energy-efficient fluid power system for HEs and reducing energy consumptions. Full article

(This article belongs to the Special Issue Advanced Fluid Power Systems and Actuators)

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22 pages, 1137 KiB

Open AccessArticle

Reuse of Exhausted Air from Multi-Actuator Pneumatic Control Systems

by Milan Šešlija, Vule Reljić, Dragan Šešlija, Slobodan Dudić, Nikolina Dakić and Zoran Jovanović

Actuators 2021, 10(6), 125; https://doi.org/10.3390/act10060125 - 7 Jun 2021

Cited by 8 | Viewed by 4575

Abstract

In order to improve the energy efficiency of multi-actuator pneumatic systems, a control scheme for the recovery of exhausted compressed air is designed and studied herein. This paper explains the procedure for the development of the balanced operation of a multi-actuator pneumatic system [...] Read more.

In order to improve the energy efficiency of multi-actuator pneumatic systems, a control scheme for the recovery of exhausted compressed air is designed and studied herein. This paper explains the procedure for the development of the balanced operation of a multi-actuator pneumatic system through the collection and reuse of exhausted compressed air. Compared with traditional motion control of pneumatic actuators, significant energy savings can be achieved, while the dynamic behavior of the cylinders from which the exhausted air is collected is maintained. Full article

(This article belongs to the Section Control Systems)

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14 pages, 3817 KiB

Open AccessCommunication

Torque Measurement Technology by Using a Magnetostrictive Ring and Multiple Magnets

by Feng Xu, Vivek Kumar Dhimole and Chongdu Cho

Actuators 2021, 10(6), 124; https://doi.org/10.3390/act10060124 - 7 Jun 2021

Cited by 6 | Viewed by 4145

Abstract

A torque measurement method that combines the inverse magnetostrictive effect with twist angle measurement has been proposed in this paper. A Kalman filter and complementary filter are applied to significantly reduce the noises and errors in the proposed method. This new measurement block [...] Read more.

A torque measurement method that combines the inverse magnetostrictive effect with twist angle measurement has been proposed in this paper. A Kalman filter and complementary filter are applied to significantly reduce the noises and errors in the proposed method. This new measurement block can detect the applied torque with an error of less than 1%. The proposed measurement method can be used in static and dynamic conditions. Full article

(This article belongs to the Special Issue New Design and Applications for Magnetoelastic Actuators)

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22 pages, 2401 KiB

Open AccessEditor’s ChoiceArticle

Control of a Rehabilitation Robotic Device Driven by Antagonistic Soft Actuators

by Haozhen Chi, Hairong Su, Wenyu Liang and Qinyuan Ren

Actuators 2021, 10(6), 123; https://doi.org/10.3390/act10060123 - 7 Jun 2021

Cited by 9 | Viewed by 4244

Abstract

Stroke is becoming a widely concerned social problem, and robot-assisted devices have made considerable contributions in the training and treatment of rehabilitation. Due to the compliance and continuous deformation capacity, rehabilitation devices driven by soft actuators are attached to widespread attention. Considering the [...] Read more.

Stroke is becoming a widely concerned social problem, and robot-assisted devices have made considerable contributions in the training and treatment of rehabilitation. Due to the compliance and continuous deformation capacity, rehabilitation devices driven by soft actuators are attached to widespread attention. Considering the large output force of pneumatic artificial muscle (PAM) and the biological musculoskeletal structure, an antagonistic PAM-driven rehabilitation robotic device is developed. To fulfill the need for control of the proposed device, a knowledge-guided data-driven modeling approach is used and an adaptive feedforward–feedback control approach is presented to ensure the motion accuracy under large deformation motion with high frequency. Finally, several simulations and experiments are carried out to evaluate the performance of the developed system, and the results show that the developed system with the proposed controller can achieve expected control performance under various operations. Full article

(This article belongs to the Special Issue Robot Control in Human-Machine Systems)

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15 pages, 2928 KiB

Open AccessArticle

A New Torque Distribution Control for Four-Wheel Independent-Drive Electric Vehicles

by Dejun Yin, Junjie Wang, Jinjian Du, Gang Chen and Jia-Sheng Hu

Actuators 2021, 10(6), 122; https://doi.org/10.3390/act10060122 - 6 Jun 2021

Cited by 17 | Viewed by 5228

Abstract

Torque distribution control is a key technique for four-wheel independent-drive electric vehicles because it significantly affects vehicle stability and handling performance, especially under extreme driving conditions. This paper, which focuses on the global yaw moment generated by both the longitudinal and the lateral [...] Read more.

Torque distribution control is a key technique for four-wheel independent-drive electric vehicles because it significantly affects vehicle stability and handling performance, especially under extreme driving conditions. This paper, which focuses on the global yaw moment generated by both the longitudinal and the lateral tire forces, proposes a new distribution control to allocate driving torques to four-wheel motors. The proposed objective function not only minimizes the longitudinal tire usage, but also make increased use of each tire to generate yaw moment and achieve a quicker yaw response. By analysis and a comparison with prior torque distribution control, the proposed control approach is shown to have better control performance in hardware-in-the-loop simulations. Full article

(This article belongs to the Special Issue Actuators for Intelligent Electric Vehicles)

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18 pages, 1232 KiB

Open AccessArticle

A Robust Noise-Free Linear Control Design for Robot Manipulator with Uncertain System Parameters

by Yi-Liang Yeh

Actuators 2021, 10(6), 121; https://doi.org/10.3390/act10060121 - 5 Jun 2021

Cited by 5 | Viewed by 2908

Abstract

In robot control, the sliding mode control is known for its robustness against external disturbances and system uncertainties. However, it has the disadvantage of control chattering, which can damage the actuator and degrade system performance. With a new stability proof, this paper presents [...] Read more.

In robot control, the sliding mode control is known for its robustness against external disturbances and system uncertainties. However, it has the disadvantage of control chattering, which can damage the actuator and degrade system performance. With a new stability proof, this paper presents an alternative simple linear feedback control that can cope with large system uncertainties and suppress large external disturbances, doing so as effectively as sliding mode control does. The advantage of using linear control is that the control law is simple and control chattering can be avoided. Moreover, a noise-free control scheme is proposed as an improvement of the feedback control; the modified design preserves the advantages of linear control and generates a chattering-free control signal even in a noisy environment. Full article

(This article belongs to the Special Issue Actuators in Robotic Control)

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21 pages, 6949 KiB

Open AccessArticle

An Intelligent Actuator of an Indoor Logistics System Based on Multi-Sensor Fusion

by Pangwei Wang, Yunfeng Wang, Xu Wang, Ying Liu and Juan Zhang

Actuators 2021, 10(6), 120; https://doi.org/10.3390/act10060120 - 4 Jun 2021

Cited by 6 | Viewed by 3447

Abstract

Integration technologies of artificial intelligence (AI) and autonomous vehicles play important roles in intelligent transportation systems (ITS). In order to achieve better logistics distribution efficiency, this paper proposes an intelligent actuator of an indoor logistics system by fusing multiple involved sensors. Firstly, an [...] Read more.

Integration technologies of artificial intelligence (AI) and autonomous vehicles play important roles in intelligent transportation systems (ITS). In order to achieve better logistics distribution efficiency, this paper proposes an intelligent actuator of an indoor logistics system by fusing multiple involved sensors. Firstly, an actuator based on a four-wheel differential chassis is equipped with sensors, including an RGB camera, a lidar and an indoor inertial navigation system, by which autonomous driving can be realized. Secondly, cross-floor positioning can be realized by multi-node simultaneous localization and mappings (SLAM) based on the Cartographer algorithm Thirdly the actuator can communicate with elevators and take the elevator to the designated delivery floor. Finally, a novel indoor route planning strategy is designed based on an A* algorithm and genetic algorithm (GA) and an actual building is tested as a scenario. The experimental results have shown that the actuator can model the indoor mapping and develop the optimal route effectively. At the same time, the actuator displays its superiority in detecting the dynamic obstacles and actively avoiding the collision in the indoor scenario. Through communicating with indoor elevators, the final delivery task can be completed accurately by autonomous driving. Full article

(This article belongs to the Special Issue Modelling, Control and Condition Monitoring of Actuator-Based Land Transport Systems)

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24 pages, 2935 KiB

Open AccessArticle

Disturbance Observer-Based Backstepping Control of Tail-Sitter UAVs

by Nihal Dalwadi, Dipankar Deb, Mangal Kothari and Stepan Ozana

Actuators 2021, 10(6), 119; https://doi.org/10.3390/act10060119 - 3 Jun 2021

Cited by 23 | Viewed by 4035

Abstract

The application scope of unmanned aerial vehicles (UAVs) is increasing along with commensurate advancements in performance. The hybrid quadrotor vertical takeoff and landing (VTOL) UAV has the benefits of both rotary-wing aircraft and fixed-wing aircraft. However, the vehicle requires a robust controller for [...] Read more.

The application scope of unmanned aerial vehicles (UAVs) is increasing along with commensurate advancements in performance. The hybrid quadrotor vertical takeoff and landing (VTOL) UAV has the benefits of both rotary-wing aircraft and fixed-wing aircraft. However, the vehicle requires a robust controller for takeoff, landing, transition, and hovering modes because the aerodynamic parameters differ in those modes. We consider a nonlinear observer-based backstepping controller in the control design and provide stability analysis for handling parameter variations and external disturbances. We carry out simulations in MATLAB Simulink which show that the nonlinear observer contributes more to robustness and overall closed-loop stability, considering external disturbances in takeoff, hovering and landing phases. The backstepping controller is capable of decent trajectory-tracking during the transition from hovering to level flight and vice versa with nominal altitude drop. Full article

(This article belongs to the Special Issue Robust, Fault-Tolerant Control Design)

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16 pages, 4867 KiB

Open AccessArticle

Design and Experimental Validation of a Fuzzy Cascade Controller for a Zero-Power Permanent Magnetic Suspension System with Variable Flux Path Control

by Haining Zhao, Ran Zhou, Yongquan Guo, Junjie Jin, Shenbo Yu and Feng Sun

Actuators 2021, 10(6), 118; https://doi.org/10.3390/act10060118 - 3 Jun 2021

Cited by 1 | Viewed by 2531

Abstract

Magnetic suspension technology has been a promising method to achieve contactless movement, and its advantages are smooth motion, no wear, no noise and low maintenance. In previous studies, the suspension force was mainly controlled by the current in the coils, which can lead [...] Read more.

Magnetic suspension technology has been a promising method to achieve contactless movement, and its advantages are smooth motion, no wear, no noise and low maintenance. In previous studies, the suspension force was mainly controlled by the current in the coils, which can lead to energy loss. To solve the problem of energy loss, we have proposed a novel zero-power permanent magnetic suspension system with variable flux path control (ZPPMSS-VFPC); moreover, the interference suppression and response of the ZPPMSS-VFPC need to be further investigated. This paper aims to improve the robustness and decrease the response time for the ZPPMSS-VFPC; as a result, a fuzzy cascade controller composed of a fuzzy controller and a cascade controller is designed and applied, in which the investigated fuzzy cascade control methods include the position loop fuzzy cascade control (PLFCC) and angle loop fuzzy cascade control (ALFCC). The structure and the working principle of the proposed ZPPMSS-VFPC are introduced, and the theoretical modeling and the fuzzy cascade controller design of the system are exhibited. An experimental setup is established to validate the simulation results and to investigate the control effect of the designed controller. The experimental results demonstrate that the response times of the fuzzy cascade controller at the displacement disturbance and the force disturbance are 0.5 s and 0.6 s faster than those of the cascade control, respectively. Furthermore, the control effect of the PLFCC is better than that of the ALFCC. Overall, the fuzzy cascade controller not only has the characteristics of strong adaptability but also has the characteristics of easy adjustment parameters, which can be applied to the complex magnetic suspension system. Full article

(This article belongs to the Section Control Systems)

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19 pages, 593 KiB

Open AccessArticle

Output Feedback Tracking Sliding Mode Control for Systems with State- and Input-Dependent Disturbances

by Yi-Liang Yeh

Actuators 2021, 10(6), 117; https://doi.org/10.3390/act10060117 - 31 May 2021

Cited by 5 | Viewed by 3338

Abstract

In this paper, output feedback tracking sliding mode control was considered for uncertain multivariable linear systems. The uncertainties included external disturbance, the system state, and control input. A new property of the loop transfer recovery (LTR) observer was first established: the state estimation [...] Read more.

In this paper, output feedback tracking sliding mode control was considered for uncertain multivariable linear systems. The uncertainties included external disturbance, the system state, and control input. A new property of the loop transfer recovery (LTR) observer was first established: the state estimation error of the LTR observer can be made arbitrarily small with respect to state- and input-dependent system uncertainties. Observer-based output feedback tracking sliding mode control using the LTR observer is presented. The proposed sliding mode control approach can maintain the boundedness of the system state and drive the system outputs arbitrarily close to the desired reference outputs; the degree of closeness was determined by a design parameter in the LTR observer. In the proposed approach, the most general and simple observer-based output feedback control formulation was used to achieve global tracking. Simulations with a two-degree-of-freedom (DOF) robotic manipulator application illustrated the claimed properties, and a peaking and chattering reduction technique was demonstrated to protect the actuator. Full article

(This article belongs to the Special Issue Actuators in Robotic Control)

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13 pages, 3761 KiB

Open AccessArticle

Dynamic Modeling and Control of Antagonistic Variable Stiffness Joint Actuator

by Ming Zhang, Pengfei Ma, Feng Sun, Xingwei Sun, Fangchao Xu, Junjie Jin and Lijin Fang

Actuators 2021, 10(6), 116; https://doi.org/10.3390/act10060116 - 31 May 2021

Cited by 6 | Viewed by 3562

Abstract

This study aims to develop a novel decoupling method for the independent control of the position and stiffness of a variable stiffness joint actuator (VSJA), which has been proven to be able to vary its stiffness in a larger range than other variable [...] Read more.

This study aims to develop a novel decoupling method for the independent control of the position and stiffness of a variable stiffness joint actuator (VSJA), which has been proven to be able to vary its stiffness in a larger range than other variable stiffness actuators. Using static analysis and the Jacobian matrix, we obtained the model of the stiffness of the robot joint actuator and dynamics. Based on the hybrid dynamic model of position and stiffness, it is possible to compensate for the torque of the variable stiffness joint actuator (VSJA) to enhance position control. Finally, after describing the actuator prototype, the established compliance control method is verified using simulation and experimental analysis. Full article

(This article belongs to the Special Issue New Design and Applications for Magnetoelastic Actuators)

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16 pages, 12308 KiB

Open AccessArticle

Three-Axis Inductive Displacement Sensor Using Phase-Sensitive Digital Signal Processing for Industrial Magnetic Bearing Applications

by Teemu Sillanpää, Alexander Smirnov, Pekko Jaatinen, Jouni Vuojolainen, Niko Nevaranta, Rafal Jastrzebski and Olli Pyrhönen

Actuators 2021, 10(6), 115; https://doi.org/10.3390/act10060115 - 31 May 2021

Cited by 13 | Viewed by 4033

Abstract

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based [...] Read more.

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding. Full article

(This article belongs to the Special Issue Magnetic Bearings: From Theory to Applications)

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24 pages, 6239 KiB

Open AccessArticle

Feedback Linearization of Inertially Actuated Jumping Robots

by Adam Cox, Pouria Razzaghi and Yildirim Hurmuzlu

Actuators 2021, 10(6), 114; https://doi.org/10.3390/act10060114 - 29 May 2021

Cited by 6 | Viewed by 3313

Abstract

Inertially Actuated Jumping Robots (IAJR) provide a promising new means of locomotion. The difficulty of IAJR is found in the hybrid nature of the ground contact/flying dynamics. Recent research studies in our Systems Lab have provided a family tree of inertially actuated locomotion [...] Read more.

Inertially Actuated Jumping Robots (IAJR) provide a promising new means of locomotion. The difficulty of IAJR is found in the hybrid nature of the ground contact/flying dynamics. Recent research studies in our Systems Lab have provided a family tree of inertially actuated locomotion systems. The proposed Tapping Robot is the most prompt member of this tree. In this paper, a feedback linearization controller is introduced to provide controllability given the 3-dimensional motion complexity. The research objective is to create a general controller that can regulate the locomotion of Inertially Actuated Jumping Robots. The expected results can specify a desired speed and/or jump height, and the controller ensures the desired values are achieved. The controller can achieve the greatest response for the Basketball Robot at a maximum jump height of 0.25 m, which is greater than the former performance with approximately 0.18 m. The design paradigm used on the Basketball Robot was extended to the Tapping Robot. The Tapping Robot achieved a stable average forward velocity of 0.0773 m/s in simulation and 0.157 m/s in experimental results, which is faster than the forward velocity of former robot, Pony III, with 0.045 m/s. Full article

(This article belongs to the Special Issue Advanced Robots: Design, Control and Application)

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18 pages, 11271 KiB

Open AccessArticle

FPGA-Based Hybrid Stepper Motor Drive System Design by Variable Structure Control

by Chiu-Keng Lai, Bo-Wei Lin, Hsiang-Yueh Lai and Guan-You Chen

Actuators 2021, 10(6), 113; https://doi.org/10.3390/act10060113 - 28 May 2021

Cited by 18 | Viewed by 6205

Abstract

A stepper motor is usually operated in position open-loop control for simplicity. However, in order to improve the transient and steady-state performances of the stepper motor-based drive system, a high performance stepper motor drive system is usually designed to feed the encoder signal [...] Read more.

A stepper motor is usually operated in position open-loop control for simplicity. However, in order to improve the transient and steady-state performances of the stepper motor-based drive system, a high performance stepper motor drive system is usually designed to feed the encoder signal back to form a closed-loop system such as a general servo motor drive, and high-performance position and speed loop controller can then be used to overcome the nonlinear characteristics of the motor, such as the cogging force and impacts from external load. On the other hand, the existed cogging force of the hybrid stepper motor must be solved to increase the positioning precision. The variable structure control (VSC) is insensitive to the bounded uncertainty and load disturbance, and has been known as a high-performance controller. A predefined sliding surface is used to shape the system performances, and incorporate with switching control to achieve the robustness property. Thus, we applied the VSC to implement the stepper motor drive system about the position and speed control, and the switching control is used to overcome the cogging force. The field programmable gate array (FPGA) is a good alternative to be used to realize a motor drive system by considering its programmable ability and diverse designing environment. It is easily developed as an intellectual property (IP) for future use or combined as a part of a large control system. This paper showed the procedures to develop the hardware circuits for the variable structure controller, and applied it to stepper motor position and velocity control. Functions such as PI controllers, dq-axis transformation and two-phase space vector space vector modulation (SVPWM) designed for the stepper motor drives are also shown in the paper. The system simulation and hardware circuit realization are based on MATLAB/Simulink, and realized on Altera FPGA. Simulations on MATLAB/Simulink with trapezoidal velocity profile command, and experiments with and without the load added are shown to demonstrate the hardware performances and correctness. Full article

(This article belongs to the Section Control Systems)

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9 pages, 2751 KiB

Open AccessCommunication

A Neural Network Based Dynamic Control Method for Soft Pneumatic Actuator with Symmetrical Chambers

by Yiqing Li, Yan Cao and Feng Jia

Actuators 2021, 10(6), 112; https://doi.org/10.3390/act10060112 - 26 May 2021

Cited by 13 | Viewed by 3291

Abstract

Dynamic modeling and control of the soft pneumatic actuators are challenging research. In this paper, a neural network based dynamic control method used for a soft pneumatic actuator with symmetrical chambers is proposed. The neural network is introduced to create the dynamic model [...] Read more.

Dynamic modeling and control of the soft pneumatic actuators are challenging research. In this paper, a neural network based dynamic control method used for a soft pneumatic actuator with symmetrical chambers is proposed. The neural network is introduced to create the dynamic model for predicting the state of the actuator. In this dynamic model, the effect of the uninflated rubber block on bending deformation is considered. Both pressures of the actuator are used for predicting the state of the actuator during the bending motion. The controller is designed based on this dynamic model for trajectory tracking control. Three types of trajectory tracking control experiments are performed to validate the proposed method. The results show that the proposed control method can control the motion of the actuator and track the trajectory effectively. Full article

(This article belongs to the Section Actuators for Robotics)

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19 pages, 458 KiB

Open AccessArticle

An Algorithm for the Broad Evaluation of Potential Matches between Actuator Concepts and Heavy-Duty Mobile Applications

by David Fassbender and Tatiana Minav

Actuators 2021, 10(6), 111; https://doi.org/10.3390/act10060111 - 25 May 2021

Cited by 3 | Viewed by 3675

Abstract

In recent years, a variety of novel actuator concepts for the implements of heavy-duty mobile machines (HDMMs) has been proposed by industry and academia. Mostly, novel concepts aim at improving the typically low energy efficiency of state-of-the-art hydraulic valve-controlled actuators. However, besides energy-efficiency, [...] Read more.

In recent years, a variety of novel actuator concepts for the implements of heavy-duty mobile machines (HDMMs) has been proposed by industry and academia. Mostly, novel concepts aim at improving the typically low energy efficiency of state-of-the-art hydraulic valve-controlled actuators. However, besides energy-efficiency, many aspects that are crucial for a successful concept integration are often neglected in studies. Furthermore, most of the time, a specific HDMM is focused as an application while other HDMM types can show very different properties that might make a novel concept less suitable. In order to take more aspects and HDMM types into account when evaluating actuator concepts, this paper proposes a novel evaluation algorithm, which calculates so-called mismatch values for each potential actuator-application match, based on different problem aspects that can indicate a potential mismatch between a certain actuator concept and an HDMM. The lower the mismatch value, which depends on actuator characteristics as well as HDMM attributes, the more potential is the match. At the same time, the modular nature of the algorithm allows to evaluate a large number of possible matches at once, with low effort. For the performance demonstration of the algorithm, 36 potential matches formed out of six actuator concepts and six HDMM types are exemplarily evaluated. The resulting actuator concept ratings for the six different HDMMs are in line with general reasoning and confirm that the evaluation algorithm is a powerful tool to get a first, quick overview of a large solution space of actuator-HDMM matches. However, analyzing the limitations of the algorithm also shows that it cannot replace conventional requirements engineering and simulation studies if detailed and reliable results are required. Full article

(This article belongs to the Special Issue Selected Papers from the 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications (IeCAT))

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18 pages, 3080 KiB

Open AccessArticle

An Optimization Design of Adaptive Cruise Control System Based on MPC and ADRC

by Zengfu Yang, Zengcai Wang and Ming Yan

Actuators 2021, 10(6), 110; https://doi.org/10.3390/act10060110 - 24 May 2021

Cited by 33 | Viewed by 6002

Abstract

In this paper, a novel adaptive cruise control (ACC) algorithm based on model predictive control (MPC) and active disturbance rejection control (ADRC) is proposed. This paper uses an MPC algorithm for the upper controller of the ACC system. Through comprehensive considerations, the upper [...] Read more.

In this paper, a novel adaptive cruise control (ACC) algorithm based on model predictive control (MPC) and active disturbance rejection control (ADRC) is proposed. This paper uses an MPC algorithm for the upper controller of the ACC system. Through comprehensive considerations, the upper controller will output desired acceleration to the lower controller. In addition, to increase the accuracy of the predictive model in the MPC controller and to address fluctuations in the vehicle’s acceleration, an MPC aided by predictive estimation of acceleration is proposed. Due to the uncertainties of vehicle parameters and the road environment, it is difficult to establish an accurate vehicle dynamic model for the lower-level controller to control the throttle and brake actuators. Therefore, feed-forward control based on a vehicle dynamic model (VDM) and compensatory control based on ADRC is used to enhance the control precision and to suppress the influence of internal or external disturbance. Finally, the proposed optimal design of the ACC system was validated in road tests. The results show that ACC with APE can accurately control the tracking of the host vehicle with less acceleration fluctuation than that of the traditional ACC controller. Moreover, when the mass of the vehicle and the slope of the road is changed, the ACC–APE–ADRC controller is still able to control the vehicle to quickly and accurately track the desired acceleration. Full article

(This article belongs to the Special Issue Vehicle Modeling and Control)

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23 pages, 9501 KiB

Open AccessEditor’s ChoiceReview

Review of Magnetoelectric Sensors

by Junqi Gao, Zekun Jiang, Shuangjie Zhang, Zhineng Mao, Ying Shen and Zhaoqiang Chu

Actuators 2021, 10(6), 109; https://doi.org/10.3390/act10060109 - 24 May 2021

Cited by 53 | Viewed by 6682

Abstract

Multiferroic magnetoelectric (ME) materials with the capability of coupling magnetization and electric polarization have been providing diverse routes towards functional devices and thus attracting ever-increasing attention. The typical device applications include sensors, energy harvesters, magnetoelectric random access memories, tunable microwave devices and ME [...] Read more.

Multiferroic magnetoelectric (ME) materials with the capability of coupling magnetization and electric polarization have been providing diverse routes towards functional devices and thus attracting ever-increasing attention. The typical device applications include sensors, energy harvesters, magnetoelectric random access memories, tunable microwave devices and ME antennas etc. Among those application scenarios, ME sensors are specifically focused in this review article. We begin with an introduction of materials development and then recent advances in ME sensors are overviewed. Engineering applications of ME sensors are followed and typical scenarios are presented. Finally, several remaining challenges and future directions from the perspective of sensor designs and real applications are included. Full article

(This article belongs to the Special Issue Advances in Piezoelectric Actuators 2022)

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17 pages, 7096 KiB

Open AccessArticle

Active Loading Control Design for a Wearable Exoskeleton with a Bowden Cable for Transmission

by Zhipeng Wang, Seungmin Rho, Chifu Yang, Feng Jiang, Zhen Ding, Chunzhi Yi and Baichun Wei

Actuators 2021, 10(6), 108; https://doi.org/10.3390/act10060108 - 24 May 2021

Cited by 9 | Viewed by 3232

Abstract

Exoskeletons with a Bowden cable for power transmission have the advantages of a concentrated mass and flexible movement. However, their integrated motor is disturbed by the Bowden cable’s friction, which limits the performance of the force loading response. In this paper, we solve [...] Read more.

Exoskeletons with a Bowden cable for power transmission have the advantages of a concentrated mass and flexible movement. However, their integrated motor is disturbed by the Bowden cable’s friction, which limits the performance of the force loading response. In this paper, we solve this problem by designing an outer-loop feedforward-feedback proportion-differentiation controller based on an inner loop disturbance observer. Firstly, the inner loop’s dynamic performance is equivalent to the designed nominal model using the proposed disturbance observer, which effectively compensates for the parameter perturbation and friction disturbance. Secondly, based on an analysis of the stability of the inner loop controller, we obtain the stability condition and discuss the influence of modeling errors on the inner loop’s dynamic performance. Thirdly, to avoid excessive noise from the force sensors being introduced into the designed disturbance observer, we propose the feedforward-feedback proportion-differentiation controller based on the nominal model and pole configuration, which improves the outer loop’s force loading performance. Experiments are conducted, which verify the effectiveness of the proposed methods. Full article

(This article belongs to the Special Issue High-Performance Compliant Robots and Soft Robots)

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20 pages, 5135 KiB

Open AccessArticle

Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

by Nakash Nazeer, Xuerui Wang and Roger M. Groves

Actuators 2021, 10(6), 107; https://doi.org/10.3390/act10060107 - 21 May 2021

Cited by 7 | Viewed by 3522

Abstract

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about [...] Read more.

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed. Full article

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

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Actuators, Volume 10, Issue 6 (June 2021) – 31 articles

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