Helmut Schlaak - Academia.edu (original) (raw)
Papers by Helmut Schlaak
The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacemen... more The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO ® software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.
2017 IEEE SENSORS
In order to calibrate a newly developed miniaturised strain gauge based 6-DOF force and torque se... more In order to calibrate a newly developed miniaturised strain gauge based 6-DOF force and torque sensor, an assembly that uses calibration weights, attached to strings and pulleys to generate forces and torques has been designed. The assembly enables a semi automatic calibration procedure. This paper describes the calculation of the uncertainty of the mechanical and electrical part of the calibration assembly according to the Guide to the Expression of Uncertainty in Measurement (GUM). Potential sources of uncertainty are extracted and the values of the uncertainties are determined. The combined uncertainty of the complete calibration assembly is calculated and the major influences are identified. Finally, suggestions for improving the uncertainty are discussed. An overall uncertainty when applying Fx = 4 N of uFx = 0.2994 N was found. This uncertainty mainly comes from temperature dependencies of the built-in resistive elements (58%) and fabrication tolerances (40%). Thus providing a homogeneous temperature distribution in a climatic room can further reduce the uncertainty. The fabrication tolerances can be reduced by optimizing the alignment during the assembly process.
Journal of the European Ceramic Society
2017 IEEE World Haptics Conference (WHC)
We present a new teleoperation setup for minimally invasive single-port surgery through natural o... more We present a new teleoperation setup for minimally invasive single-port surgery through natural orifices. The system consists of an intra-corporal parallel slave robot with two instrument arms and a corresponding master interface with four degrees of freedom and grasping. The master interface mimicks the slave robot kinematics to prevent non-achievable movements. With a workspace of ⊘ 60 mm × 85 mm, interaction forces of up to 5 N and mean speeds of up to 327 mm/s the robot is designed to perform a rectum resection intervention, an operation hardly possible with conventional laparoscopic instruments. In this work, we address several ergonomic aspects of the setup, including surgeon's pose, movement scaling, visual feedback, and haptic feedback. Two experiments were performed to investigate the accuracy and dexterity of the robotic system compared to conventional single-port systems. We found a significant decrease of errors in a point-and-touch-task when using the robot, but no effect on the duration of the task. Surgeons were able to perform suturing and knotting tasks as well as a gall bladder extraction in a porcine model with the robot in an hands on experiment. These experiments showed a good intuitivity and a high instrument control precision as described by the participants.
Der vorliegende Bericht des Instituts fur Elektromechanische Konstruktionen am Fachbereich Elektr... more Der vorliegende Bericht des Instituts fur Elektromechanische Konstruktionen am Fachbereich Elektrotechnik und Informationstechnik der Technischen Universitat Darmstadt, der alle zwei Jahre erscheint, gibt einen Uberblick zur geleisteten Arbeit in Lehre und Forschung im Zeitraum 2009 bis 2010.
2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2016
Single port surgery is an innovative approach in the field of minimally invasive surgery. Althoug... more Single port surgery is an innovative approach in the field of minimally invasive surgery. Although several telemanipulators exist to perform operations through only a single incision they all suffer from the lack of haptic feedback. To generate kinesthetic feedback the intracorporeal forces need to be measured, which is a challenging task. To overcome these limitations we investigate in this paper the force sensing capability of a new single port robot that has two parallelkinematic manipulators. Because of the rigidity and excellent controllability the tip force is measured using proximally arranged force sensors. To minimize friction effects a longitudinal vibration of 6 Hz with an amplitude of 20 μm is applied to the manipulator while the tip force is varied in the three main coordinate axes. Within the analysis 32320 values are investigated showing that a vibration has a significant impact and dramatically improves the signal quality by minimizing the crosstalk by a factor of up...
Anisotropic friction generated by tilted carbon fiber arrays may be used to transform vibrations ... more Anisotropic friction generated by tilted carbon fiber arrays may be used to transform vibrations into a continuous motion of a rotor. This principle will be used in this work in a planar rotary motor with unimorph cantilevers as a vibration source. In this paper we research the deflection-force characteristics of the tilted carbon fiber arrays for the use in this motor. Therefore a measurement setup is introduced to quantify the generated friction force of the carbon fiber arrays. The measured deflection-force curves suggest a linear dependency starting at deflections of 100 micrometer. Below these deflections, the behavior of the arrays is measured to be nonlinear. A variation of the angle between the carbon fiber arrays and the contact surface below 3deg does not have an influence on the characteristic in this region of low deflections. Using the measurements and an electromechanical model, the desired cantilever geometries for the motor are derived. The optimized cantilevers are ...
In this paper, we present a novel binary threshold sensor, which is able to use the energy provid... more In this paper, we present a novel binary threshold sensor, which is able to use the energy provided directly from the measured relative humidity of the ambient air to mechanically switch an electrical micro contact. This zeropower switch behavior is realized by using the humiditysensitive volume swelling of a polymer layer as the detection element deflecting a mechanical deformable silicon boss structure, thus closing the electrical contacts of the switch. For the humidity-sensitive sensor switch considered here, a hydrogel blend of 15 wt% poly(vinyl alcohol) (PVA) and 7.5 wt% poly(acryl acid) (PAA) was used. According to first swelling experiments with a prototype the provided deflection of approximately 36 μm of a 20 μm thin silicon flexure plate seems very promising.
The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacemen... more The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO ® software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.
2017 IEEE SENSORS
In order to calibrate a newly developed miniaturised strain gauge based 6-DOF force and torque se... more In order to calibrate a newly developed miniaturised strain gauge based 6-DOF force and torque sensor, an assembly that uses calibration weights, attached to strings and pulleys to generate forces and torques has been designed. The assembly enables a semi automatic calibration procedure. This paper describes the calculation of the uncertainty of the mechanical and electrical part of the calibration assembly according to the Guide to the Expression of Uncertainty in Measurement (GUM). Potential sources of uncertainty are extracted and the values of the uncertainties are determined. The combined uncertainty of the complete calibration assembly is calculated and the major influences are identified. Finally, suggestions for improving the uncertainty are discussed. An overall uncertainty when applying Fx = 4 N of uFx = 0.2994 N was found. This uncertainty mainly comes from temperature dependencies of the built-in resistive elements (58%) and fabrication tolerances (40%). Thus providing a homogeneous temperature distribution in a climatic room can further reduce the uncertainty. The fabrication tolerances can be reduced by optimizing the alignment during the assembly process.
Journal of the European Ceramic Society
2017 IEEE World Haptics Conference (WHC)
We present a new teleoperation setup for minimally invasive single-port surgery through natural o... more We present a new teleoperation setup for minimally invasive single-port surgery through natural orifices. The system consists of an intra-corporal parallel slave robot with two instrument arms and a corresponding master interface with four degrees of freedom and grasping. The master interface mimicks the slave robot kinematics to prevent non-achievable movements. With a workspace of ⊘ 60 mm × 85 mm, interaction forces of up to 5 N and mean speeds of up to 327 mm/s the robot is designed to perform a rectum resection intervention, an operation hardly possible with conventional laparoscopic instruments. In this work, we address several ergonomic aspects of the setup, including surgeon's pose, movement scaling, visual feedback, and haptic feedback. Two experiments were performed to investigate the accuracy and dexterity of the robotic system compared to conventional single-port systems. We found a significant decrease of errors in a point-and-touch-task when using the robot, but no effect on the duration of the task. Surgeons were able to perform suturing and knotting tasks as well as a gall bladder extraction in a porcine model with the robot in an hands on experiment. These experiments showed a good intuitivity and a high instrument control precision as described by the participants.
Der vorliegende Bericht des Instituts fur Elektromechanische Konstruktionen am Fachbereich Elektr... more Der vorliegende Bericht des Instituts fur Elektromechanische Konstruktionen am Fachbereich Elektrotechnik und Informationstechnik der Technischen Universitat Darmstadt, der alle zwei Jahre erscheint, gibt einen Uberblick zur geleisteten Arbeit in Lehre und Forschung im Zeitraum 2009 bis 2010.
2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2016
Single port surgery is an innovative approach in the field of minimally invasive surgery. Althoug... more Single port surgery is an innovative approach in the field of minimally invasive surgery. Although several telemanipulators exist to perform operations through only a single incision they all suffer from the lack of haptic feedback. To generate kinesthetic feedback the intracorporeal forces need to be measured, which is a challenging task. To overcome these limitations we investigate in this paper the force sensing capability of a new single port robot that has two parallelkinematic manipulators. Because of the rigidity and excellent controllability the tip force is measured using proximally arranged force sensors. To minimize friction effects a longitudinal vibration of 6 Hz with an amplitude of 20 μm is applied to the manipulator while the tip force is varied in the three main coordinate axes. Within the analysis 32320 values are investigated showing that a vibration has a significant impact and dramatically improves the signal quality by minimizing the crosstalk by a factor of up...
Anisotropic friction generated by tilted carbon fiber arrays may be used to transform vibrations ... more Anisotropic friction generated by tilted carbon fiber arrays may be used to transform vibrations into a continuous motion of a rotor. This principle will be used in this work in a planar rotary motor with unimorph cantilevers as a vibration source. In this paper we research the deflection-force characteristics of the tilted carbon fiber arrays for the use in this motor. Therefore a measurement setup is introduced to quantify the generated friction force of the carbon fiber arrays. The measured deflection-force curves suggest a linear dependency starting at deflections of 100 micrometer. Below these deflections, the behavior of the arrays is measured to be nonlinear. A variation of the angle between the carbon fiber arrays and the contact surface below 3deg does not have an influence on the characteristic in this region of low deflections. Using the measurements and an electromechanical model, the desired cantilever geometries for the motor are derived. The optimized cantilevers are ...
In this paper, we present a novel binary threshold sensor, which is able to use the energy provid... more In this paper, we present a novel binary threshold sensor, which is able to use the energy provided directly from the measured relative humidity of the ambient air to mechanically switch an electrical micro contact. This zeropower switch behavior is realized by using the humiditysensitive volume swelling of a polymer layer as the detection element deflecting a mechanical deformable silicon boss structure, thus closing the electrical contacts of the switch. For the humidity-sensitive sensor switch considered here, a hydrogel blend of 15 wt% poly(vinyl alcohol) (PVA) and 7.5 wt% poly(acryl acid) (PAA) was used. According to first swelling experiments with a prototype the provided deflection of approximately 36 μm of a 20 μm thin silicon flexure plate seems very promising.