DOI: 10.5061/dryad.jq2bvq8gv
title: Data from: 3D printed digital pneumatic logic for the control of soft robotic actuators

description: Soft robots are paving their way to catch up with the application range of
 metal-based machines and to occupy fields which are challenging for
 traditional machines. Pneumatic actuators play an important role in this
 development, allowing the construction of bioinspired motion systems.
 Pneumatic logic gates provide a powerful alternative for controlling
 pressure-activated soft robots, which are often controlled by metallic
 valves and electric circuits. Many existing approaches for fully compliant
 pneumatic control logic suffer from high manual effort and low pressure
 tolerance. In our work, we invented 3D printable, pneumatic logic gates
 that perform Boolean operations and imitate electric circuits. Within 7
 hours, an FDM printer is able to produce a module that serves as either an
 OR, AND or NOT gate; the logic function is defined by the assigned input
 signals. The gate contains two alternately acting pneumatic valves, whose
 work principle is based on the interaction of pressurized chambers and a
 3D printed 1 mm tube inside. The gate design does not require any kind of
 support material for its hollow parts, which makes the modules ready to
 use directly after printing. Depending on the chosen material, the modules
 can operate on a pressure supply between 80 and over 750 kPa. The
 capabilities of the invented gates were verified by implementing an
 electronics-free drink dispenser based on a pneumatic ring oscillator and
 a 1-bit memory. Their high compliance is demonstrated by driving a car
 over a fully flexible, 3D printed robotic walker controlled by an
 integrated circuit.
description: The described pneumatic elements were fabricated on a 3D printing
 platform as detailed in Conrad et al. (<em>https://doi.org/10.1007/978-3-030-64313-3_6</em>). The flexible parts, like valves and logic gates, described in this work have been printed in one continuous process with “Recreus FilaFlex TPU A60” (shore hardness A 63), “Recreus FilaFlex TPU A70”  and “Recreus FilaFlex TPU A82” with fitting print parameters (please see supplements). In all pneumatic experiments, the pressurization of chambers and channels was controlled by a custom test stand. This setup contained six pneumatic proportional valves driven by a LabView program. The software supports the creation of linear patterns and repeating sequences, which simplified the systematic characterization by applying rising and falling pressure ramps to the logic elements. For the characterization of a single valve, unused inlets were sealed and the gate output socket was connected to atmospheric pressure via a flow sensor to measure the volumetric stream. After changing the state on the input connectors, the software waited four seconds for the module to reach a new static internal flow and then recorded this value. To test the behavior of the complete logic gate, a pressure sensor was connected to the output. Here, the applied pressure was measured continuously to characterize the dynamic behavior. For deformation experiments we used a mechanical testing machine equipped for compression tests up to 10 kN. The data was processed using RStudio 2023.03.1+446 "Cherry Blossom" Release (6e31ffc3ef2a1f81d377eeccab71ddc11cfbd29e, 2023-05-09) for windows. The same software was used to create figures.
description: # 3D printed digital pneumatic logic for the control of soft robotic
 actuators [https://doi.org/10.5061/dryad.jq2bvq8gv
 ](https://doi.org/10.5061/dryad.jq2bvq8gv) This dataset contains the data
 and scripts that were used to generate the figures of the main text and
 supplements. All data was generated with pneumatic elements that were
 fabricated on a 3D printing platform as detailed in Conrad et al. (2020)
 (). The flexible parts,
 like valves and logic gates, described in this work have been printed in
 one continuous process with 'Recreus FilaFlex TPU A60' (shore
 hardness A 63), 'Recreus FilaFlex TPU A70' and 'Recreus
 FilaFlex TPU A82' with fitting print parameters (detailed in the
 supplements). This includes pneumatic connectors, channels and expandable
 membranes. Most parameters were set in the software 'PrusaSlic3r
 2.4', which was used to prepare our models for printing. In a post
 processing step the files generated by the software were additionally
 modified to adapt the flow rate to the special needs of the flexible
 filament. ## Description of the data and file structure In the dataset the
 files are sorted by the figure or table they belong to. Inside the
 respective folders there are the raw data as well as the RStudio scripts
 that were used to calculate statistical tests as well as generate the
 figures. ## Explanation for data files Figure2File1.csv: Column 1 consists
 of the material of the used PLG in Shore hardness. Column 2 is the ID of
 the PLG. Column 3 is the valve of the PLG, where V1 is the normally-open
 valve and V2 is the normally-closed valve. Column 4 is the pressure at the
 socket S_t that was required to close the respective valve in bar.
 Figure2File2.txt: Column 1 shows the set pressure in bar at the input
 socket S_c1 of the PLG. Column 2 shows the measured mean pressure in bar
 at the input socket S_c1 for that pressure step. Column 3 is the mean
 pressure in bar at the socket S_t. Column 4 is the mean volumetric flow in
 ln/min through the PLG. Columns 5,6 and 7 are the respective standard
 deviations of the measured values for that pressure step. Column 8 is used
 to differentiate between the two experiments of measuring flow
 ('Durchfluss') and closing the valve ('Schliessen').
 Column 9 specifies the tested valve and column 10 is the concatenated
 value of column 8 and 9. Figure2File3.txt: The columns are the same than
 in Figure2File2, but instead of specifying the valve, column 9 shows the
 direction of the signal (ASC = ascending/rising = 0 -&gt; 1, DESC =
 descending/falling = 1 -&gt; 0). Figure3File1-125.txt: Column 1 shows the
 set pressure in bar at the input socket S_t of the PLG. Column 2 shows the
 measured mean pressure in bar at the socket S_t. Column 3 shows the
 measured mean pressure in bar at the socket S_c. Column 4 is the mean
 volumetric flow in ln/min through the PLG. Columns 5,6 and 7 are the
 respective standard deviations of the measured values for that pressure
 step. Column 8 shows the direction of the signal (ASC = ascending/rising =
 0 -&gt; 1, DESC = descending/falling = 1 -&gt; 0). Column 9 shows the set
 system pressure in bar at the socket S_p+. Column 10 specifies the valve
 of the PLG, where V1 is the normally-open valve and V2 is the
 normally-closed valve. Column 11 is the concatenated value of columns 8, 9
 and 10. Figure3File1-250.txt: The columns are the same than in
 Figure3File1-125, but the system pressure is at 250 kPa instead of the 125
 kPa. Figure3File2-125.txt: The columns are the same than in
 Figure3File1-125, but the values are from the NC valve instead of the NO
 valve. Figure3File2-250.txt: The columns are the same than in
 Figure3File1-250, but the values are from the NC valve instead of the NO
 valve. Figure3File3.txt: This file shows the maximum values for each
 combination of PLG, system pressure and direction of the signal. Column 1
 shows the set pressure in bar at the input socket S_t of the PLG. Column 2
 shows the measured mean pressure in bar at the socket S_t. Column 3 shows
 the measured mean pressure in bar at the socket S_p+. Column 4 is the mean
 volumetric flow in ln/min through the PLG. Column 5, 6 and 7 are the
 respective standard deviations of the measured values for that pressure
 step. Column 8 shows the direction of the signal (ASC = ascending/rising =
 0 -&gt; 1, DESC = descending/falling = 1 -&gt; 0). Column 9 shows the set
 system pressure in bar at the socket S_p+. Column 10 is the concatenated
 values of column 8 and 9. Column 11 is the ID of the PLG.
 Figure4File1.txt: This file shows the measurement for the NOT-PLG. Column
 one shows the time in seconds. Column 2 shows the measured pressure at
 socket S_p+ in bar. Column 3 shows the measured pressure at socket S_c1 in
 bar. Column 4 shows the measured pressure at socket S_t in bar. Column 5
 shows the measured pressure at socket S_c2 in bar. Column 6 shows the
 measure pressure at socket S_out in bar. Figure5File1.txt: This file shows
 the measurement for the AND-PLG. Column one shows the time in seconds.
 Column 2 shows the measured pressure at socket S_p+ in bar. Column 3 shows
 the measured pressure at socket S_t in bar. Column 4 shows the measured
 pressure at socket S_c2 in bar. Column 5 shows the measured pressure at
 socket S_out in bar. Figure5File2.txt: This file shows the measurement for
 the OR-PLG. Column one shows the time in seconds. Column 2 shows the
 measured pressure at socket S_p+ in bar. Column 3 shows the measured
 pressure at socket S_c1 in bar. Column 4 shows the measured pressure at
 socket S_t in bar. Column 5 shows the measured pressure at socket S_c2 in
 bar. Column 6 shows the measure pressure at socket S_out in bar.
 Figure6File1.txt: Column 1 shows the set system pressure in bar. Column 2
 shows the measured mean time in seconds needed for an ascending input
 signal at socket S_t to create a status change in the output socket S_out.
 Column 3 shows the measured mean time in seconds needed for a descending
 input signal at socket S_t to create a status change in the output socket
 S_out. Columns 4 and 5 show the respective standard deviations of the
 measure values. Column 6 specifies the number of PLG connected in a row.
 Figure6File2.xlsx: Columns 1 to 6 show the same data than in
 Figure6File1.txt. They were used to calculate the normal equations from
 the observation equations and to fit a trend to the normal equations. The
 trend for the ascending slope is calculated in columns 8 to 16, the trend
 for the descending slope is calculated in columns 18 to 26. This was then
 used as the trend seen in Figure 6 B and C. Additionally, we subtracted
 the delay for a theoretical number of gates of 0, in order to remove the
 delay introduced by the measuring instruments. We included a reference in
 the script "Figure6.R" to show this. FigureS1File1.csv: Column 1
 shows the set system pressure in bar. Column specifies the tested valve .
 Column 3 shows the direction of the signal (ASC = ascending/rising = 0
 -&gt; 1, DESC = descending/falling = 1 -&gt; 0). Column 4 is the measured
 mean transition interval for the switching of the valve in bar.
 FigureS1File2.csv: This file has the same data than FigureS1File1.csv, but
 the two directions of the signal are pooled into one dataset. It is also
 the dataset used for figure S1. Please see the script "Figure
 S1.R" for the statistics. FigureS4File1.txt: Column 1 shows the
 maximum compression force in kN. Column 2 shows the ID of the PLG. Column
 3 specifies which channel is beeing measured (1 = S_c1, 2 = S_c2). Column
 4 shows the measured mean volumetric flow through that channel in ln/min.
 Column 5 shows the standard deviation of the measured mean volumetric
 flow. FigureS5File1.csv: Column 1 shows the ID of the PLG. Column 2 shows
 the maximum compression force in kN. Column 3 shows the direction of the
 signal (ASC = ascending/rising = 0 -&gt; 1, DESC = descending/falling = 1
 -&gt; 0). Column 4 shows the repetition. Column 5 is the beginning of the
 edge of the signal in seconds. Column 6 is the end of the signal in
 seconds. Column 7 is the difference between the end and the start of the
 signal in seconds. Column shows the difference between the end and the
 start of the signal in seconds after subtracting the delay the measuring
 system introduces (calculated in Figure6File2.xlsx). TableS1File1.xlsx:
 Column shows the Shore hardness on the A scale of the PLG. Column 2 shows
 the ID of the PLG. Column 3 shows the maximum air pressure it resisted in
 bar. ## Code/Software All scripts were made and run in RStudio. The
 version used is RStudio 2023.03.1+446 "Cherry Blossom" Release
 (6e31ffc3ef2a1f81d377eeccab71ddc11cfbd29e, 2023-05-09) for windows.