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Christopher Niezrecki - One of the best experts on this subject based on the ideXlab platform.
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Investigation of THUNDER (TM) Actuators as Underwater Propulsors
Journal of Intelligent Materials Systems and Structures, 2002Co-Authors: Sivakumar Balakrishnan, Christopher NiezreckiAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator Thin Layer Composite Unimorph Ferroelectric Driver and Sensor (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement of the order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electro-mechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's nontraditional actuating architecture, high voltage requirements, and its electrical nonlinearity. This work experimentally determines the mechanical displacement and the electrical power consumption of the THUNDER Actuators used as underwater propulsors. An estimate of a lower bound of the thrust that can be generated by the clamshell actuator is obtained. It is found that the actuator has a peak flow rate of approximately 1500 cm3/s and can generate a peak thrust greater than approximately 4.5 N. This preliminary analysis neglected the pressure forces acting on the actuator and therefore, the actual thrust is not computed. It is found that the average electrical power consumed by two THUNDER Actuators placed in a clamshell configuration operating at 14 Hz is approximately 8 W, which is significantly less than that consumed by other autonomous underwater vehicles. The displacement response and the current draw of the Actuators are determined to be nonlinear. The result of this work indicates that the use of THUNDER Actuators has great potential to create an underwater propulsor that has low power consumption, can operate at great depths, and eliminates the need for seals, bearings and a propeller.
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Investigation of THUNDER[sup TM] Actuators as Underwater Propulsors.
Journal of Intelligent Material Systems & Structures, 2002Co-Authors: Sivakumar Balakrishnan, Christopher NiezreckiAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator Thin Layer Composite Unimorph Ferroelectric Driver and Sensor (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement of the order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electromechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's nontraditional actuating architecture, high voltage requirements, and its electrical nonlinearity. This work experimentally determines the mechanical displacement and the electrical power consumption of the THUNDER Actuators used as underwater propulsors. An estimate of a lower bound of the thrust that can be generated by the clamshell actuator is obtained. It is found that the actuator has a peak flow rate of approximately 1500cm³/s and can generate a peak thrust greater than approximately 4.5N. This preliminary analysis neglected the pressure forces acting on the actuator and therefore, the actual thrust is not computed. It is found that the average electrical power consumed by two THUNDER Actuators placed in a clamshell configuration operating at ∼14Hz is approximately 8 W, which is significantly less than that consumed by other autonomous underwater vehicles. The displacement response and the current draw of the Actuators are determined to be nonlinear. The result of this work indicates that the use of THUNDER Actuators has great potential to create an underwater propulsor that has low power consumption, can operate at great depths, and eliminates the... [ABSTRACT FROM AUTHOR]
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Power characterization of THUNDER (TM) Actuators as underwater propulsors
Smart Structures and Materials 2001: Smart Structures and Integrated Systems, 2001Co-Authors: Christopher Niezrecki, Sreeram Balakrishnan, Sivakumar Balakrishnan, Suhrid Balakrishnan, Shidin BalakrishnanAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement on order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electromechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's non traditional actuating architecture, high voltage requirements, and its electrical non-linearity. The work presented experimentally determines the electrical power consumption and mechanical displacement of THUNDER Actuators used as underwater propulsors. It is found that the electrical power consumption of the clamshell actuator investigated is significantly less than that consumed by other autonomous under water vehicles. The potential thrust generated by such a device remains to be quantified.
Jamie Paik - One of the best experts on this subject based on the ideXlab platform.
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Soft pneumatic gelatin actuator for edible robotics
IEEE International Conference on Intelligent Robots and Systems, 2017Co-Authors: Jun Shintake, Harshal Sonar, Egor Piskarev, Jamie Paik, Dario FloreanoAbstract:We present a fully edible pneumatic actuator based on gelatin-glycerol composite. The actuator is monolithic, fabricated via a molding process, and measures 90 mm in length, 20 mm in width, and 17 mm in thickness. Thanks to the composite mechanical characteristics similar to those of silicone elastomers, the actuator exhibits a bending angle of 170.3 {\deg} and a blocked force of 0.34 N at the applied pressure of 25 kPa. These values are comparable to elastomer based pneumatic Actuators. As a validation example, two Actuators are integrated to form a gripper capable of handling various objects, highlighting the high performance and applicability of the edible actuator. These edible Actuators, combined with other recent edible materials and electronics, could lay the foundation for a new type of edible robots.
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Design and Analysis of a Soft Pneumatic Actuator with Origami Shell Reinforcement
Soft Robotics, 2016Co-Authors: Laura Paez, Gunjan Agarwal, Jamie PaikAbstract:Abstract Soft pneumatic Actuators (SPAs) are versatile robotic components enabling diverse and complex soft robot hardware design. However, due to inherent material characteristics exhibited by their primary constitutive material, silicone rubber, they often lack robustness and repeatability in performance. In this article, we present a novel SPA-based bending module design with shell reinforcement. The bidirectional soft actuator presented here is enveloped in a Yoshimura patterned origami shell, which acts as an additional protection layer covering the SPA while providing specific bending resilience throughout the actuator's range of motion. Mechanical tests are performed to characterize several shell folding patterns and their effect on the actuator performance. Details on design decisions and experimental results using the SPA with origami shell modules and performance analysis are presented; the performance of the bending module is significantly enhanced when reinforcement is provided by the shell. W...
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Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices
Scientific Reports, 2016Co-Authors: Gunjan Agarwal, Nicolas Besuchet, Basile Audergon, Jamie PaikAbstract:Soft Actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces Actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes' (linear and bending Actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft Actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.
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IROS - Soft pneumatic actuator with adjustable stiffness layers for Multi-DoF Actuation
2015 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2015Co-Authors: Amir Firouzeh, Marco Salerno, Jamie PaikAbstract:The soft pneumatic Actuators (SPAs) are a solution toward the highly customizable and light Actuators with the versatility of actuation modes, and an inherent compliance. Such flexibility allows SPAs to be considered as alternative Actuators for wearable rehabilitative devices and search and rescue robots. The actuator material and air-chamber design dictate the actuator's mechanical performance. Therefore, each actuator design with a single pressure source produces a highly customized motion but only a single degree of freedom (DoF). We present a novel design and fabrication method for a SPA with different modes of actuation using integrated adjustable stiffness layers (ASLs). Unlike the most SPA designs where one independent chamber is needed for each mode of actuation, here we have a single chamber that drives three different modes of actuation by activating different combinations of ASLs. Adapting customized micro heaters and thermistors for modulating the temperature and stiffness of ASLs, we considerably broaden the work space of the SPA actuator. Here, a thorough characterization of the materials and the modeling of the actuator are presented. We propose a design methodology for developing application specific Actuators with multi-DoFs that are light and compact.
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Soft pneumatic actuator with adjustable stiffness layers for Multi-DoF Actuation
2015 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2015Co-Authors: Amir Firouzeh, Marco Salerno, Jamie PaikAbstract:The soft pneumatic Actuators (SPAs) are a solution toward the highly customizable and light Actuators with the versatility of actuation modes, and an inherent compliance. Such flexibility allows SPAs to be considered as alternative Actuators for wearable rehabilitative devices and search and rescue robots. The actuator material and air-chamber design dictate the actuator's mechanical performance. Therefore, each actuator design with a single pressure source produces a highly customized motion but only a single degree of freedom (DoF). We present a novel design and fabrication method for a SPA with different modes of actuation using integrated adjustable stiffness layers (ASLs). Unlike the most SPA designs where one independent chamber is needed for each mode of actuation, here we have a single chamber that drives three different modes of actuation by activating different combinations of ASLs. Adapting customized micro heaters and thermistors for modulating the temperature and stiffness of ASLs, we considerably broaden the work space of the SPA actuator. Here, a thorough characterization of the materials and the modeling of the actuator are presented. We propose a design methodology for developing application specific Actuators with multi-DoFs that are light and compact.
Sivakumar Balakrishnan - One of the best experts on this subject based on the ideXlab platform.
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Investigation of THUNDER (TM) Actuators as Underwater Propulsors
Journal of Intelligent Materials Systems and Structures, 2002Co-Authors: Sivakumar Balakrishnan, Christopher NiezreckiAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator Thin Layer Composite Unimorph Ferroelectric Driver and Sensor (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement of the order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electro-mechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's nontraditional actuating architecture, high voltage requirements, and its electrical nonlinearity. This work experimentally determines the mechanical displacement and the electrical power consumption of the THUNDER Actuators used as underwater propulsors. An estimate of a lower bound of the thrust that can be generated by the clamshell actuator is obtained. It is found that the actuator has a peak flow rate of approximately 1500 cm3/s and can generate a peak thrust greater than approximately 4.5 N. This preliminary analysis neglected the pressure forces acting on the actuator and therefore, the actual thrust is not computed. It is found that the average electrical power consumed by two THUNDER Actuators placed in a clamshell configuration operating at 14 Hz is approximately 8 W, which is significantly less than that consumed by other autonomous underwater vehicles. The displacement response and the current draw of the Actuators are determined to be nonlinear. The result of this work indicates that the use of THUNDER Actuators has great potential to create an underwater propulsor that has low power consumption, can operate at great depths, and eliminates the need for seals, bearings and a propeller.
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Investigation of THUNDER[sup TM] Actuators as Underwater Propulsors.
Journal of Intelligent Material Systems & Structures, 2002Co-Authors: Sivakumar Balakrishnan, Christopher NiezreckiAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator Thin Layer Composite Unimorph Ferroelectric Driver and Sensor (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement of the order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electromechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's nontraditional actuating architecture, high voltage requirements, and its electrical nonlinearity. This work experimentally determines the mechanical displacement and the electrical power consumption of the THUNDER Actuators used as underwater propulsors. An estimate of a lower bound of the thrust that can be generated by the clamshell actuator is obtained. It is found that the actuator has a peak flow rate of approximately 1500cm³/s and can generate a peak thrust greater than approximately 4.5N. This preliminary analysis neglected the pressure forces acting on the actuator and therefore, the actual thrust is not computed. It is found that the average electrical power consumed by two THUNDER Actuators placed in a clamshell configuration operating at ∼14Hz is approximately 8 W, which is significantly less than that consumed by other autonomous underwater vehicles. The displacement response and the current draw of the Actuators are determined to be nonlinear. The result of this work indicates that the use of THUNDER Actuators has great potential to create an underwater propulsor that has low power consumption, can operate at great depths, and eliminates the... [ABSTRACT FROM AUTHOR]
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Power characterization of THUNDER (TM) Actuators as underwater propulsors
Smart Structures and Materials 2001: Smart Structures and Integrated Systems, 2001Co-Authors: Christopher Niezrecki, Sreeram Balakrishnan, Sivakumar Balakrishnan, Suhrid Balakrishnan, Shidin BalakrishnanAbstract:Piezoelectric Actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material Actuators stems from their high mechanical energy density. A relatively new actuator (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based Actuators. It is capable of providing a displacement on order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electromechanical efficiency of these Actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator's non traditional actuating architecture, high voltage requirements, and its electrical non-linearity. The work presented experimentally determines the electrical power consumption and mechanical displacement of THUNDER Actuators used as underwater propulsors. It is found that the electrical power consumption of the clamshell actuator investigated is significantly less than that consumed by other autonomous under water vehicles. The potential thrust generated by such a device remains to be quantified.
Luis Sentis - One of the best experts on this subject based on the ideXlab platform.
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Design and control considerations for high-performance series elastic Actuators
IEEE ASME Transactions on Mechatronics, 2014Co-Authors: Nicholas Paine, Sehoon Oh, Luis SentisAbstract:This paper discusses design and control of a prismatic series elastic actuator with high mechanical power output in a small and lightweight form factor. A design is introduced that pushes the performance boundary of electric series elastic Actuators by using high motor voltage coupled with an efficient drivetrain to enable large continuous actuator force while retaining speed. Compact size is achieved through the use of a novel piston-style ball screw support mechanism and a concentric compliant element. Generic models for two common series elastic actuator configurations are introduced and compared. These models are then used to develop controllers for force and position tracking based on combinations of PID, model-based, and disturbance observer control structures. Finally, our actuator's performance is demonstrated through a series of experiments designed to operate the actuator at the limits of its mechanical and control capability.
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A new prismatic series elastic actuator with compact size and high performance
2012 IEEE International Conference on Robotics and Biomimetics ROBIO 2012 - Conference Digest, 2012Co-Authors: Nicholas Paine, Luis SentisAbstract:This paper discusses design and control of a prismatic series elastic actuator with high mechanical power output in a small and lightweight form factor. We introduce a design that pushes the performance boundary of electric series elastic Actuators by using high motor voltage coupled with an efficient drivetrain to enable large continuous actuator force while retaining speed. Compact size is achieved through the use of a novel piston-style ball screw support mechanism and a concentrically placed compliant element. We develop controllers for force and position tracking based on combinations of PID, model-based, and disturbance observer control structures. Finally, we demonstrate our actuator's performance with a series of experiments designed to operate the actuator at the limits of its mechanical and control capability.
Gunjan Agarwal - One of the best experts on this subject based on the ideXlab platform.
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Design and Analysis of a Soft Pneumatic Actuator with Origami Shell Reinforcement
Soft Robotics, 2016Co-Authors: Laura Paez, Gunjan Agarwal, Jamie PaikAbstract:Abstract Soft pneumatic Actuators (SPAs) are versatile robotic components enabling diverse and complex soft robot hardware design. However, due to inherent material characteristics exhibited by their primary constitutive material, silicone rubber, they often lack robustness and repeatability in performance. In this article, we present a novel SPA-based bending module design with shell reinforcement. The bidirectional soft actuator presented here is enveloped in a Yoshimura patterned origami shell, which acts as an additional protection layer covering the SPA while providing specific bending resilience throughout the actuator's range of motion. Mechanical tests are performed to characterize several shell folding patterns and their effect on the actuator performance. Details on design decisions and experimental results using the SPA with origami shell modules and performance analysis are presented; the performance of the bending module is significantly enhanced when reinforcement is provided by the shell. W...
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Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices
Scientific Reports, 2016Co-Authors: Gunjan Agarwal, Nicolas Besuchet, Basile Audergon, Jamie PaikAbstract:Soft Actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces Actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes' (linear and bending Actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft Actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.