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In recent years, tissue engineering with mechanical stimulation has received considerable attention. In order to manipulate tissue samples, there is a need for electromechanical devices, such as constant-force actuators, with integrated deflection measurement. In this paper, we present an electrostatic constant-force actuator allowing the generation of a constant force and a simultaneous displacement measurement intended for tissue characterization. The system combines a comb drive structure and a constant-force spring system. A theoretical overview of both subsystems, as well as actual measurements of a demonstrator system, are provided. Based on the silicon-on-insulator technology, the fabrication process of a moveable system with an extending measurement tip is shown. Additionally, we compare measurement results with simulations. Our demonstrator reaches a constant-force of 79 ± 2
Anna Christina Thewes; Philip Schmitt; Philipp Löhler; Martin Hoffmann. Design and Characterization of an Electrostatic Constant-Force Actuator Based on a Non-Linear Spring System. Actuators 2021, 10, 192 .
AMA StyleAnna Christina Thewes, Philip Schmitt, Philipp Löhler, Martin Hoffmann. Design and Characterization of an Electrostatic Constant-Force Actuator Based on a Non-Linear Spring System. Actuators. 2021; 10 (8):192.
Chicago/Turabian StyleAnna Christina Thewes; Philip Schmitt; Philipp Löhler; Martin Hoffmann. 2021. "Design and Characterization of an Electrostatic Constant-Force Actuator Based on a Non-Linear Spring System." Actuators 10, no. 8: 192.
We present the design, fabrication, and characterization of a MEMS-based 3-bit Digital-to-Analog Converter (DAC) that allows the generation of large displacements. The DAC consists of electrostatic bending-plate actuators that are connected to a mechanical amplifier (mechAMP), enabling the amplification of the DAC output displacement. Based on a parallel binary-encoded voltage signal, the output displacement of the system can be controlled in an arbitrary order. Considering the system design, we present a simplified analytic model, which was confirmed by FE simulation results. The fabricated systems showed a total stroke of approx. 149.5 ± 0.3 µm and a linear stepwise displacement of 3 bit correlated to 23 ≙ eight defined positions at a control voltage of 60 V. The minimum switching time between two input binary states is 0.1 ms. We present the experimental characterization of the system and the DAC and derive the influence of the mechAMP on the functionality of the DAC. Furthermore, the resonant behavior and the switching speed of the system are analyzed. By changing the electrode activation sequence, 27 defined positions are achieved upgrading the 3-bit systems into a 3-tri-state (33) system.
Lisa Schmitt; Philip Schmitt; Martin Hoffmann. 3-Bit Digital-to-Analog Converter with Mechanical Amplifier for Binary Encoded Large Displacements. Actuators 2021, 10, 182 .
AMA StyleLisa Schmitt, Philip Schmitt, Martin Hoffmann. 3-Bit Digital-to-Analog Converter with Mechanical Amplifier for Binary Encoded Large Displacements. Actuators. 2021; 10 (8):182.
Chicago/Turabian StyleLisa Schmitt; Philip Schmitt; Martin Hoffmann. 2021. "3-Bit Digital-to-Analog Converter with Mechanical Amplifier for Binary Encoded Large Displacements." Actuators 10, no. 8: 182.
In this paper we introduce the concept, modelling and analysis of triangular and sinusoidal springs intended for large in-plane translational displacements for MEMS-guiding applications. The proposed spring systems combine the advantages of minimal space requirement, low stiffness in the axial direction and high mechanical resistance in off-axis directions. An analytical model for the description of the force-displacement characteristic of triangular springs is derived considering typical mechanical constraints. Based on the model, geometrical parameters of the springs influencing linearity and selectivity with respect to the in- and off-axis stiffness are analyzed. The validity of the models is demonstrated by finite element analysis and experimental verification realized by silicon-on-insulator demonstrators. [2020-0360]
Philip Schmitt; Lisa Schmitt; Nick Tsivin; Martin Hoffmann. Highly Selective Guiding Springs for Large Displacements in Surface MEMS. Journal of Microelectromechanical Systems 2021, PP, 1 -15.
AMA StylePhilip Schmitt, Lisa Schmitt, Nick Tsivin, Martin Hoffmann. Highly Selective Guiding Springs for Large Displacements in Surface MEMS. Journal of Microelectromechanical Systems. 2021; PP (99):1-15.
Chicago/Turabian StylePhilip Schmitt; Lisa Schmitt; Nick Tsivin; Martin Hoffmann. 2021. "Highly Selective Guiding Springs for Large Displacements in Surface MEMS." Journal of Microelectromechanical Systems PP, no. 99: 1-15.
In this paper, we introduce a compliant mechanical amplifier (mechAMP) suitable for the sensitivity enhancement in MEMS sensor applications. The design, fabrication and characterization of a planar compliant amplifier mechanism is presented with special focus on the kinematic and static system modelling of the displacement and force amplification. We show that the proposed system can also be applied as mechanical stiffness transformer for the adaption of mechanical signals or as mechanical transformer for MEMS actuators. Based on a kinematic model, a compact mechanism with a system size of 930 μm x 2080 μm and a displacement amplification ratio of 200 with an output displacement in a range of 100 μm was designed. The fabrication of the system was carried out using silicon-on-insulator (SOI) technology. Experimentally, we could verify an amplification ratio of 197.9 for the designed and fabricated system which corresponds to the analytic model by a deviation of about 1%. [2019-0228]
Philip Schmitt; Martin Hoffmann. Engineering a Compliant Mechanical Amplifier for MEMS Sensor Applications. Journal of Microelectromechanical Systems 2020, 29, 214 -227.
AMA StylePhilip Schmitt, Martin Hoffmann. Engineering a Compliant Mechanical Amplifier for MEMS Sensor Applications. Journal of Microelectromechanical Systems. 2020; 29 (2):214-227.
Chicago/Turabian StylePhilip Schmitt; Martin Hoffmann. 2020. "Engineering a Compliant Mechanical Amplifier for MEMS Sensor Applications." Journal of Microelectromechanical Systems 29, no. 2: 214-227.
We present a passive force and displacement sensor based on a compliant mechanical amplifier combined with a micromechanical analog-to-digital converter that allows to amplify and convert a displacement signal in the nanometer range directly into an electrically readable binary code without the need of electrical energy for the conversion itself. The presented compliant amplifier achieves a displacement amplification ratio of about 100 within an input range of $1.3\ \mu \mathrm{m}$ , which enables a resolution of 40 nm steps by using a 5-bit mechanical analog-to-digital converter. Furthermore, a method is proposed to implement a pre-defined transfer function into the mechanical A/D converter in order to linearize or benchmark a non-linear primary displacement signal.
Philip Schmitt; Martin Hoffmann. Direct Binary Encoding of Displacements on the Nano-Scale. 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS) 2020, 677 -680.
AMA StylePhilip Schmitt, Martin Hoffmann. Direct Binary Encoding of Displacements on the Nano-Scale. 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS). 2020; ():677-680.
Chicago/Turabian StylePhilip Schmitt; Martin Hoffmann. 2020. "Direct Binary Encoding of Displacements on the Nano-Scale." 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS) , no. : 677-680.
Autonomous sensors are of interest in all cases where a continuous power source is not available or difficult to realize. Besides harvesting of electrical energy for a complex storage system, it is of interest to directly store an event in a non-electrical storage, but in a way that allows a later electrical read-out. Therefore, a miniaturized micromechanical binary counter is presented, which enables counting of threshold events, such as exceeding temperature limits or high mechanical shocks. An electro-mechanical digital-to-analog converter integrated in the binary counter is demonstrated as an option for monolithic electrical read-out of the mechanically stored information.
Philip Schmitt; Hannes Mehner; Martin Hoffmann. A Micromechanical Binary Counter with MEMS-Based Digital-to-Analog Converter. Proceedings 2018, 2, 807 .
AMA StylePhilip Schmitt, Hannes Mehner, Martin Hoffmann. A Micromechanical Binary Counter with MEMS-Based Digital-to-Analog Converter. Proceedings. 2018; 2 (13):807.
Chicago/Turabian StylePhilip Schmitt; Hannes Mehner; Martin Hoffmann. 2018. "A Micromechanical Binary Counter with MEMS-Based Digital-to-Analog Converter." Proceedings 2, no. 13: 807.
This paper describes a concept for a passive microfluidic time-temperature indicator (TTI) intended for intelligent food packaging. A microfluidic system is presented that makes use of the temperature-dependent flow of suitable food ingredients in a microcapillary. Based on the creeping distance inside the capillary, the time-temperature integral can be determined. A demonstrator of the microsystem has been designed, fabricated and characterised using liquid sugar alcohols as indicator fluids. To enable a first wireless read-out of the passive TTI, the sensor was read out using a commercial RFID equipment, and capacitive measurements have been carried out.
P Schmitt; K Wedrich; L Müller; H Mehner; M Hoffmann. Design, fabrication and characterisation of a microfluidic time-temperature indicator. Journal of Physics: Conference Series 2017, 922, 012004 .
AMA StyleP Schmitt, K Wedrich, L Müller, H Mehner, M Hoffmann. Design, fabrication and characterisation of a microfluidic time-temperature indicator. Journal of Physics: Conference Series. 2017; 922 (1):012004.
Chicago/Turabian StyleP Schmitt; K Wedrich; L Müller; H Mehner; M Hoffmann. 2017. "Design, fabrication and characterisation of a microfluidic time-temperature indicator." Journal of Physics: Conference Series 922, no. 1: 012004.
M. Hoffmann; K. Wedrich; P. Schmitt; H. Mehner; R. Jurisch. Non-electrical Sensing and Storing an Alternative to Electrical Energy Harvesting. Procedia Engineering 2016, 168, 1621 -1625.
AMA StyleM. Hoffmann, K. Wedrich, P. Schmitt, H. Mehner, R. Jurisch. Non-electrical Sensing and Storing an Alternative to Electrical Energy Harvesting. Procedia Engineering. 2016; 168 ():1621-1625.
Chicago/Turabian StyleM. Hoffmann; K. Wedrich; P. Schmitt; H. Mehner; R. Jurisch. 2016. "Non-electrical Sensing and Storing an Alternative to Electrical Energy Harvesting." Procedia Engineering 168, no. : 1621-1625.