Machine-induced vibrations and their control represent, for several reasons, a crucial design issue for buildings, and especially for industrial facilities. A special attention is required, at the early design stage, for the structural and dynamic performance assessment of the load-bearing members, given that they should be optimally withstand potentially severe machinery operations. To this aim, however, the knowledge of the input vibration source is crucial. This paper investigates a case-study eyewear factory built in Italy during 2019 and characterized by various non-isolated computer numerical control (CNC) vertical machinery centers mounted on the inter-story floor. Accordingly, the structure started to suffer for pronounced resonance issues. Following the past experience, this paper reports on the efficiency of a coupled experimental-numerical method for generalized predictive and characterization studies. The advantage is that the machinery features are derived from on-site experiments on the equipment, as well as on the floor. The experimental outcomes are then assessed and integrated with the support of Finite Element (FE) numerical simulations, to explore the resonance performance of the floor. The predictability of marked resonance issues is thus analyzed, with respect to the reference performance indicators.
{"title":"Predictivity of CNC machine-induced vibrations on inter-story floors based on coupled experimental-numerical investigations","authors":"Chiara Bedon, Enrico Bergamo, Marco Fasan","doi":"10.3390/iecat2020-08529","DOIUrl":"https://doi.org/10.3390/iecat2020-08529","url":null,"abstract":"Machine-induced vibrations and their control represent, for several reasons, a crucial design issue for buildings, and especially for industrial facilities. A special attention is required, at the early design stage, for the structural and dynamic performance assessment of the load-bearing members, given that they should be optimally withstand potentially severe machinery operations. To this aim, however, the knowledge of the input vibration source is crucial. This paper investigates a case-study eyewear factory built in Italy during 2019 and characterized by various non-isolated computer numerical control (CNC) vertical machinery centers mounted on the inter-story floor. Accordingly, the structure started to suffer for pronounced resonance issues. Following the past experience, this paper reports on the efficiency of a coupled experimental-numerical method for generalized predictive and characterization studies. The advantage is that the machinery features are derived from on-site experiments on the equipment, as well as on the floor. The experimental outcomes are then assessed and integrated with the support of Finite Element (FE) numerical simulations, to explore the resonance performance of the floor. The predictability of marked resonance issues is thus analyzed, with respect to the reference performance indicators.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126640889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electro-hydrostatic actuators (EHAs) combine the advantages of electric and hydraulic actuators, and it is resulting in a preferable solution for the heavy load actuation in applications such as aircrafts, ships, construction machines, and machine tools. The required power level of the EHA is increasing because the EHA is being introduced to heavier vehicles such as submarines and heavy launch vehicles. Thus, a 30 kW EHA is under development for launch vehicles, which simultaneously require high dynamic performance, light weight, high efficiency, etc. However, the existing optimization design methods of EHA do not take in account all the requirements, especially the dynamic performance. Therefore, a dedicate multi-objective optimization design method is proposed for the preliminary design for the 30 kW EHA. In this study, firstly, the design requirements were analyzed for the launch vehicle application, and the objectives and the constraints of the optimization design were defined for the 30 kW EHA. Secondly, dedicate models were developed for evaluating each objective or constraint. Among these models, the EHA weight is estimated through the scaling law method and analytical calculation, the bandwidth is estimated based on the cascaded control method, the energy consumption is evaluated by the inverse dynamic simulation utilizing dedicate Matlab codes. Thirdly, the multi-objective EHA optimization design was implemented based on the genetic algorithm. Hereby, the key parameters were decided for the proposed EHA design. At last, the optimization design results were evaluated through simulation analysis, which demonstrated that the 30 kW EHA achieved more than 10 Hz bandwidth with under 70 kg weight while the efficiency was also optimized. In addition, the proposed method is shown to be competent for the preliminary design of high power EHAs which are subject to multiple critical requirements.
{"title":"Multi-objective optimization design of a 30 kW Electro-hydrostatic Actuator","authors":"Chi Zhang, Xudong Han, T. Minav, Y. Fu","doi":"10.3390/iecat2020-08525","DOIUrl":"https://doi.org/10.3390/iecat2020-08525","url":null,"abstract":"Electro-hydrostatic actuators (EHAs) combine the advantages of electric and hydraulic actuators, and it is resulting in a preferable solution for the heavy load actuation in applications such as aircrafts, ships, construction machines, and machine tools. The required power level of the EHA is increasing because the EHA is being introduced to heavier vehicles such as submarines and heavy launch vehicles. Thus, a 30 kW EHA is under development for launch vehicles, which simultaneously require high dynamic performance, light weight, high efficiency, etc. However, the existing optimization design methods of EHA do not take in account all the requirements, especially the dynamic performance. Therefore, a dedicate multi-objective optimization design method is proposed for the preliminary design for the 30 kW EHA. In this study, firstly, the design requirements were analyzed for the launch vehicle application, and the objectives and the constraints of the optimization design were defined for the 30 kW EHA. Secondly, dedicate models were developed for evaluating each objective or constraint. Among these models, the EHA weight is estimated through the scaling law method and analytical calculation, the bandwidth is estimated based on the cascaded control method, the energy consumption is evaluated by the inverse dynamic simulation utilizing dedicate Matlab codes. Thirdly, the multi-objective EHA optimization design was implemented based on the genetic algorithm. Hereby, the key parameters were decided for the proposed EHA design. At last, the optimization design results were evaluated through simulation analysis, which demonstrated that the 30 kW EHA achieved more than 10 Hz bandwidth with under 70 kg weight while the efficiency was also optimized. In addition, the proposed method is shown to be competent for the preliminary design of high power EHAs which are subject to multiple critical requirements.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"385 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116328003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: For the longest time, valve-controlled, centralized hydraulic systems have been the state-of-the-art technology to actuate heavy-duty mobile machine (HDMM) implements. Due to the typically low energy efficiency of those systems, a high number of promising, more-efficient actuator concepts has been proposed by academia as well as industry over the last decades as potential replacements for valve control—e.g., independent metering, displacement control, different types of electro-hydraulic actuators (EHAs), electro-mechanic actuators, or hydraulic transformers. This paper takes a closer look on specific HDMM applications for these actuator concepts to figure out where which novel concept can be a better alternative to conventional actuator concepts, and where novel concepts might fail to improve. For this purpose, a novel evaluation algorithm for actuator–HDMM matches is developed based on problem aspects that can indicate an unsuitable actuator–HDMM match. To demonstrate the functionality of the match evaluation algorithm, four actuator concepts and four HDMM types are analyzed and rated in order to form 16 potential actuator–HDMM matches that can be evaluated by the novel algorithm. The four actuator concepts comprise a conventional valve-controlled concept and three different types of EHAs. The HDMM types are excavator, wheel loader, backhoe, and telehandler. Finally, the evaluation of the 16 matches results in 16 mismatch values , of which the lowest indicates the “perfect match”. Low mismatch values could be found in general for EHAs in combination with most HDMMs but also for a valve-controlled actuator concept in combination with a backhoe. Furthermore, an analysis of the concept limitations with suggestions for improvement is included.
{"title":"Finding the Perfect Match—Different Heavy-Duty Mobile Applications Call for Different Actuators","authors":"David Fassbender, Tatina Minav","doi":"10.3390/iecat2020-08524","DOIUrl":"https://doi.org/10.3390/iecat2020-08524","url":null,"abstract":": For the longest time, valve-controlled, centralized hydraulic systems have been the state-of-the-art technology to actuate heavy-duty mobile machine (HDMM) implements. Due to the typically low energy efficiency of those systems, a high number of promising, more-efficient actuator concepts has been proposed by academia as well as industry over the last decades as potential replacements for valve control—e.g., independent metering, displacement control, different types of electro-hydraulic actuators (EHAs), electro-mechanic actuators, or hydraulic transformers. This paper takes a closer look on specific HDMM applications for these actuator concepts to figure out where which novel concept can be a better alternative to conventional actuator concepts, and where novel concepts might fail to improve. For this purpose, a novel evaluation algorithm for actuator–HDMM matches is developed based on problem aspects that can indicate an unsuitable actuator–HDMM match. To demonstrate the functionality of the match evaluation algorithm, four actuator concepts and four HDMM types are analyzed and rated in order to form 16 potential actuator–HDMM matches that can be evaluated by the novel algorithm. The four actuator concepts comprise a conventional valve-controlled concept and three different types of EHAs. The HDMM types are excavator, wheel loader, backhoe, and telehandler. Finally, the evaluation of the 16 matches results in 16 mismatch values , of which the lowest indicates the “perfect match”. Low mismatch values could be found in general for EHAs in combination with most HDMMs but also for a valve-controlled actuator concept in combination with a backhoe. Furthermore, an analysis of the concept limitations with suggestions for improvement is included.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123400678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. M. R. M. Ferreira, Guilherme de Paula Rúbio, F. H. L. Brandão, Arthur Mazzini da Mata, Natália Batista Castilho de Avellar, João Paulo Fernandes Bonfim, Leandro Gonzaga Tonelli, T. E. Silva, R. Dutra, A. M. V. N. V. Petten, C. Vimieiro
Subjects with impaired upper limb have motor limitations that interfere with their ability to independently perform activities of daily living. An alternative rehabilitation consists of Robot Assisted Therapy, a method that increases the intensity, dosage and consequently the effectiveness of the treatment. Therefore, news robotic actuators were developed, external to the device with components manufactured using additive manufacturing, to assist the upper limb rehabilitation. One of them aims to actively perform the finger extension and the flexion passively, using a servo motor coupled to a rope system. At the elbow, one DC-motor combined with a gear-box, was coupled to a system of pulleys and ropes designed to actively perform your flexion and extension movements. Triggering the system was used an Arduino-NANO® and a mobile application for Android. Evaluating the prototype performance, the fingers opening and closing movements were performed, together with the elbow flexion and extension and the gripping of objects in three post-stroke volunteers. It was observed with these actuators the volunteer has the ability to perform the proposed movements, using a torque of 12 Nm for the elbow movement and 0.8 Nm for the fingers opening. The volunteers showed forearm pronation during the tests, causing a torsion in the elbow support structure, making structural reinforcement necessary in the region, which resulted in an increase in the component's weight. After that, the pronation problem was solved and the movements could be performed. Therefore, this work presented new robotic devices composed by more robust motors and actuators, which are located externally to the device structure. Despite not being portable for everyday use, the device was able to perform the movements effectively, being possible to use it exclusively in rehabilitation clinics, so that it helps in the recovery of upper limb.
{"title":"ROBOTIC ORTHOSIS FOR UPPER LIMB REHABILITATION","authors":"F. M. R. M. Ferreira, Guilherme de Paula Rúbio, F. H. L. Brandão, Arthur Mazzini da Mata, Natália Batista Castilho de Avellar, João Paulo Fernandes Bonfim, Leandro Gonzaga Tonelli, T. E. Silva, R. Dutra, A. M. V. N. V. Petten, C. Vimieiro","doi":"10.3390/iecat2020-08519","DOIUrl":"https://doi.org/10.3390/iecat2020-08519","url":null,"abstract":"Subjects with impaired upper limb have motor limitations that interfere with their ability to independently perform activities of daily living. An alternative rehabilitation consists of Robot Assisted Therapy, a method that increases the intensity, dosage and consequently the effectiveness of the treatment. Therefore, news robotic actuators were developed, external to the device with components manufactured using additive manufacturing, to assist the upper limb rehabilitation. One of them aims to actively perform the finger extension and the flexion passively, using a servo motor coupled to a rope system. At the elbow, one DC-motor combined with a gear-box, was coupled to a system of pulleys and ropes designed to actively perform your flexion and extension movements. Triggering the system was used an Arduino-NANO® and a mobile application for Android. Evaluating the prototype performance, the fingers opening and closing movements were performed, together with the elbow flexion and extension and the gripping of objects in three post-stroke volunteers. It was observed with these actuators the volunteer has the ability to perform the proposed movements, using a torque of 12 Nm for the elbow movement and 0.8 Nm for the fingers opening. The volunteers showed forearm pronation during the tests, causing a torsion in the elbow support structure, making structural reinforcement necessary in the region, which resulted in an increase in the component's weight. After that, the pronation problem was solved and the movements could be performed. Therefore, this work presented new robotic devices composed by more robust motors and actuators, which are located externally to the device structure. Despite not being portable for everyday use, the device was able to perform the movements effectively, being possible to use it exclusively in rehabilitation clinics, so that it helps in the recovery of upper limb.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127828741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
“HAPA” stands for High-Authority Piezoelectric Actuator, which describes high-performance piezoelectric actuators of large stroke and blocking force. “HAPAs” are made possible by high-bending-stiffness connectors that connect multiple units of piezoceramic stacks into a 2-level actuation structure. Present HAPA actuators are fitted with commercial piezoceramic stacks. For instance, a “HAPA-(2+2)” comprises 4 lead zirconate titanate (PZT) stacks, 2 in the upper level with displacement projecting upward and 2 in the lower level with displacement projecting downward. They not only double the axial displacement of individual stacks with only fractional increase in device length but also are of 1.5 to 3 larger blocking force depending on the actual design. “FTA” stands for Flextensional Actuator, in which the horizontal extensional displacement of PZT stacks is amplified to yield much larger contractional vertical displacement via a diamond-shaped elastic frame structure. A range of new FTAs has been developed by us using single or multiple units of PZT stacks, of which the performances are described in this work. “HD-FTA” stands for HAPA-Driven Flextensional Actuator, in which HAPA piezoelectric actuators are used as the motor section to drive diamond-shaped elastic members of various designs for further displacement amplification. Several HD-FTAs, driven by a HAPA-(2+2) actuator, have been developed. Compared with standard FTAs of comparable stroke, HD-FTAs display a higher working load but of smaller overall length. “HAPA”, “FTA”, and “HD-FTA” piezoelectric actuators find applications when a smaller actuator length is advantageous in addition to the required moderate-to-large displacement and working load.
{"title":"New “HAPA”, “FTA” and “HD-FTA” Piezoelectric Actuators","authors":"D. Lin, Xia Yuexue, J. Koh, F. Lim, L. Lim","doi":"10.3390/iecat2020-08507","DOIUrl":"https://doi.org/10.3390/iecat2020-08507","url":null,"abstract":"“HAPA” stands for High-Authority Piezoelectric Actuator, which describes high-performance piezoelectric actuators of large stroke and blocking force. “HAPAs” are made possible by high-bending-stiffness connectors that connect multiple units of piezoceramic stacks into a 2-level actuation structure. Present HAPA actuators are fitted with commercial piezoceramic stacks. For instance, a “HAPA-(2+2)” comprises 4 lead zirconate titanate (PZT) stacks, 2 in the upper level with displacement projecting upward and 2 in the lower level with displacement projecting downward. They not only double the axial displacement of individual stacks with only fractional increase in device length but also are of 1.5 to 3 larger blocking force depending on the actual design. “FTA” stands for Flextensional Actuator, in which the horizontal extensional displacement of PZT stacks is amplified to yield much larger contractional vertical displacement via a diamond-shaped elastic frame structure. A range of new FTAs has been developed by us using single or multiple units of PZT stacks, of which the performances are described in this work. “HD-FTA” stands for HAPA-Driven Flextensional Actuator, in which HAPA piezoelectric actuators are used as the motor section to drive diamond-shaped elastic members of various designs for further displacement amplification. Several HD-FTAs, driven by a HAPA-(2+2) actuator, have been developed. Compared with standard FTAs of comparable stroke, HD-FTAs display a higher working load but of smaller overall length. “HAPA”, “FTA”, and “HD-FTA” piezoelectric actuators find applications when a smaller actuator length is advantageous in addition to the required moderate-to-large displacement and working load.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129422950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, several legged/wheeled robots have been developed, and their effective functionality in locomotion on uneven terrains has been proved. Many robotics researchers have been focusing on improving the locomotion speed as well as the stability and robustness of such robots. High-speed locomotion of robots is, however, subject to various design challenges, especially in the development of actuators. The robotic applications that require high-speed motion in high-torque operations along with the ability to manage dynamic physical interactions are not satisfied by the conventional robotic actuators deploying high-reduction gearings. In this work, we present a quasi-direct-drive actuator designed for continuous high-speed motions in high torque, such as wheeled motions in mobile robots or joint motions in dynamic-legged robots. The presented actuator exploits low-reduction gearing so that it can render over 26 Nm of continuous torque, while the actuator speed can exceed 37 rad/s. Such characteristics enable the exhibition of dynamic motions and can deal with large external impacts. The selection of the motor and design of the gearing unit was carried out iteratively so that commercial items with minimum customization could be employed and the outer diameters of the motor and the gearbox could match. A single-level planetary gearbox was devised for the reduction unit to ensure high back-drivability and transparency of the actuator, thereby making the actuator robust against external impacts and allowing for accurate torque control using motor current measurement. The gear set design was carried out based on the AGMA gear torque calculation. Given the radial space required for the gearbox to deal with the torque requirements, the actuator motor was chosen to be small in height (pancake type), which ensures high torque density within smaller dimensions at high-speed operation. The mechanical design of the actuator is presented in this paper, and the actuator’s specifications in terms of size and performance are compared with those of similar state-of-the-art actuators.
{"title":"Design of a Quasi Direct drive Actuator for Dynamic Motions","authors":"A. Singh, Navvab Kashiri, N. Tsagarakis","doi":"10.3390/iecat2020-08516","DOIUrl":"https://doi.org/10.3390/iecat2020-08516","url":null,"abstract":"In recent years, several legged/wheeled robots have been developed, and their effective functionality in locomotion on uneven terrains has been proved. Many robotics researchers have been focusing on improving the locomotion speed as well as the stability and robustness of such robots. High-speed locomotion of robots is, however, subject to various design challenges, especially in the development of actuators. The robotic applications that require high-speed motion in high-torque operations along with the ability to manage dynamic physical interactions are not satisfied by the conventional robotic actuators deploying high-reduction gearings. In this work, we present a quasi-direct-drive actuator designed for continuous high-speed motions in high torque, such as wheeled motions in mobile robots or joint motions in dynamic-legged robots. The presented actuator exploits low-reduction gearing so that it can render over 26 Nm of continuous torque, while the actuator speed can exceed 37 rad/s. Such characteristics enable the exhibition of dynamic motions and can deal with large external impacts. The selection of the motor and design of the gearing unit was carried out iteratively so that commercial items with minimum customization could be employed and the outer diameters of the motor and the gearbox could match. A single-level planetary gearbox was devised for the reduction unit to ensure high back-drivability and transparency of the actuator, thereby making the actuator robust against external impacts and allowing for accurate torque control using motor current measurement. The gear set design was carried out based on the AGMA gear torque calculation. Given the radial space required for the gearbox to deal with the torque requirements, the actuator motor was chosen to be small in height (pancake type), which ensures high torque density within smaller dimensions at high-speed operation. The mechanical design of the actuator is presented in this paper, and the actuator’s specifications in terms of size and performance are compared with those of similar state-of-the-art actuators.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128583401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The pronation/supination of the forearm are important movements to properly accomplish the activities of daily living. While several exoskeletons have been proposed for the rehabilitation of the arm, few of them have actively implemented the movements of pronation/supination. Often, the addition of this degree of freedom to the mechanism results in a bulky and heavy structure. Consequently, the overall exoskeleton is too big for a wearable solution. This paper proposes a digital prototype and kinematic evaluation of a cable-driven orthosis for pronation/supination movement assistance. The actuator is based on an open ring (semi-circle) to be attached to the forearm, while a stationary guide drives the ring into a rotary movement. By considering anthropomorphic data in the design stage, it is possible to develop a rigid, compact, and high power to weight ratio solution for the actuator responsible for pronation and supination. The proposed actuator can achieve the full range of motion for the activities of daily living and 83% of the rotation of the forearm total range of motion with a total mass of only 150 g.
{"title":"Design of a Cable-driven Actuator for Pronation and Supination of the Forearm to Integrate an Active Arm Orthosis","authors":"E. Dias, R. Andrade","doi":"10.3390/iecat2020-08511","DOIUrl":"https://doi.org/10.3390/iecat2020-08511","url":null,"abstract":": The pronation/supination of the forearm are important movements to properly accomplish the activities of daily living. While several exoskeletons have been proposed for the rehabilitation of the arm, few of them have actively implemented the movements of pronation/supination. Often, the addition of this degree of freedom to the mechanism results in a bulky and heavy structure. Consequently, the overall exoskeleton is too big for a wearable solution. This paper proposes a digital prototype and kinematic evaluation of a cable-driven orthosis for pronation/supination movement assistance. The actuator is based on an open ring (semi-circle) to be attached to the forearm, while a stationary guide drives the ring into a rotary movement. By considering anthropomorphic data in the design stage, it is possible to develop a rigid, compact, and high power to weight ratio solution for the actuator responsible for pronation and supination. The proposed actuator can achieve the full range of motion for the activities of daily living and 83% of the rotation of the forearm total range of motion with a total mass of only 150 g.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123985729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Shape memory alloys and polymers are a class of smart materials that remember a pre-trained shape or form when exposed to an appropriate temperature. In this work, shape memory alloys consisting of wires, 1-way springs, and 2-way springs are described; an open-loop control of shape memory alloys and polymers is also implemented. Since the amount of electric current that flows through a wire is directly proportional to temperature, control of the electric circuit is used for open-loop temperature control. The designed smart control is applied to rotate a lever mechanism through the conversion of the linear motion of the shape memory alloy (SMA) into the rotational motion of the lever through the tapping of a piezoelectric transducer to deliver the open-loop control. When the piezo transducer is deformed by mechanical stress via tapping, striking, or any other mechanical stimulus, it produces an electrical signal, which when sent to the microelectronic circuit activates the SMA. The implemented system can be applied in robotic systems and autonomous applications.
{"title":"Open-Loop Control Design of Shape Memory Alloys and Polymers through Tapping Motion","authors":"V. Oguntosin","doi":"10.3390/iecat2020-08512","DOIUrl":"https://doi.org/10.3390/iecat2020-08512","url":null,"abstract":": Shape memory alloys and polymers are a class of smart materials that remember a pre-trained shape or form when exposed to an appropriate temperature. In this work, shape memory alloys consisting of wires, 1-way springs, and 2-way springs are described; an open-loop control of shape memory alloys and polymers is also implemented. Since the amount of electric current that flows through a wire is directly proportional to temperature, control of the electric circuit is used for open-loop temperature control. The designed smart control is applied to rotate a lever mechanism through the conversion of the linear motion of the shape memory alloy (SMA) into the rotational motion of the lever through the tapping of a piezoelectric transducer to deliver the open-loop control. When the piezo transducer is deformed by mechanical stress via tapping, striking, or any other mechanical stimulus, it produces an electrical signal, which when sent to the microelectronic circuit activates the SMA. The implemented system can be applied in robotic systems and autonomous applications.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124186709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soft actuators are the compliant-material based devices capable of producing large deformation upon external stimuli. Dielectric elastomer actuators(DEA) are a type of soft actuators that operate on voltage stimuli. Apart from soft robotics, these actuators can serve many novel applications, for example, tunable optical gratings, lens, diffusers, smart windows and so on. This talk presents our current work on tunable smart windows which can regulate the light transmittance and the sound absorption. This smart window can promote daylighting while maintaining privacy by switching between transparent and opaque. As a tunable optical surface scatters, it turns transparent with smooth surfaces like a flat glass; but it turns ‘opaque’ (translucent) with the micro-rough surface. The surface roughness is varied by means of surface micro-wrinkling or unfolding using dielectric elastomer actuation. In addition, this smart window is equipped with another layer of transparent micro-perforated dielectric elastomer actuator (DEA), which acts like Helmholtz resonators serving as a tunable and broader sound absorber. It can electrically tune its absorption spectrum to match the noise frequency for maximum acoustic absorption. The membrane tension and perforation size are tuned using DEA activation to tune its acoustic resonant frequency. Such novel smart window can be made as cheap as glass due to its simple all-solid-state construction. They are used to green building and could potentially enhance the urban livability.
{"title":"Multifunctional Smart Window based on Dielectric Elastomer Actuator","authors":"M. Shrestha, G. Lau, Zhenbo Lu","doi":"10.3390/iecat2020-08509","DOIUrl":"https://doi.org/10.3390/iecat2020-08509","url":null,"abstract":"Soft actuators are the compliant-material based devices capable of producing large deformation upon external stimuli. Dielectric elastomer actuators(DEA) are a type of soft actuators that operate on voltage stimuli. Apart from soft robotics, these actuators can serve many novel applications, for example, tunable optical gratings, lens, diffusers, smart windows and so on. This talk presents our current work on tunable smart windows which can regulate the light transmittance and the sound absorption. This smart window can promote daylighting while maintaining privacy by switching between transparent and opaque. As a tunable optical surface scatters, it turns transparent with smooth surfaces like a flat glass; but it turns ‘opaque’ (translucent) with the micro-rough surface. The surface roughness is varied by means of surface micro-wrinkling or unfolding using dielectric elastomer actuation. In addition, this smart window is equipped with another layer of transparent micro-perforated dielectric elastomer actuator (DEA), which acts like Helmholtz resonators serving as a tunable and broader sound absorber. It can electrically tune its absorption spectrum to match the noise frequency for maximum acoustic absorption. The membrane tension and perforation size are tuned using DEA activation to tune its acoustic resonant frequency. Such novel smart window can be made as cheap as glass due to its simple all-solid-state construction. They are used to green building and could potentially enhance the urban livability.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133702881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Malindu Ehalagastanne, Ishan Sumanasekara, Hishan Wickramasinghe, I. Nissanka, Gayani K. Nandasiri
This paper presents a study on design and development of an alternating pressure overlay consists of inflatable mini air-bladders, which could be used in relieving and reducing tissue pressure for the treatment of pressure ulcers. Pressure ulcers, which are predominant in the bony prominences of the body, is a skin deformity due to the limitation of blood circulation to the muscle tissues as a result of high pressures applied on the skin for longer durations. This research aims to design miniaturized air bladders which could provide alternating pressure sequences for the treatment of the pressure ulcers. The optimally designed geometries of mini air-bladders provide proper envelopment of the patient’s body and create a high resolution of pressure distribution. The optimum geometry and the 3-D deformation profile of the mini air-bladders are analyzed using the finite element method. Furthermore, the real-time interface pressure profile between the body and the overlay is mapped by using the back pressure of mini air-bladders. The actuator system includes an integrated control unit that regulates the internal pressures via electro-pneumatic valves operated based on the backpressure sensor feedback. This actuator system provides the alternating pressure patterns required for inflation and deflation of the mini air-bladders controlling the airflow of the support surface, providing proper pressure distributions to heal the ulcers.
{"title":"Towards the Development of an Alternating Pressure Overlay for the Treatment of Pressure Ulcers Using Miniaturized Air Cells","authors":"Malindu Ehalagastanne, Ishan Sumanasekara, Hishan Wickramasinghe, I. Nissanka, Gayani K. Nandasiri","doi":"10.3390/iecat2020-08522","DOIUrl":"https://doi.org/10.3390/iecat2020-08522","url":null,"abstract":"This paper presents a study on design and development of an alternating pressure overlay consists of inflatable mini air-bladders, which could be used in relieving and reducing tissue pressure for the treatment of pressure ulcers. Pressure ulcers, which are predominant in the bony prominences of the body, is a skin deformity due to the limitation of blood circulation to the muscle tissues as a result of high pressures applied on the skin for longer durations. This research aims to design miniaturized air bladders which could provide alternating pressure sequences for the treatment of the pressure ulcers. The optimally designed geometries of mini air-bladders provide proper envelopment of the patient’s body and create a high resolution of pressure distribution. The optimum geometry and the 3-D deformation profile of the mini air-bladders are analyzed using the finite element method. Furthermore, the real-time interface pressure profile between the body and the overlay is mapped by using the back pressure of mini air-bladders. The actuator system includes an integrated control unit that regulates the internal pressures via electro-pneumatic valves operated based on the backpressure sensor feedback. This actuator system provides the alternating pressure patterns required for inflation and deflation of the mini air-bladders controlling the airflow of the support surface, providing proper pressure distributions to heal the ulcers.","PeriodicalId":152837,"journal":{"name":"Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134062264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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