DOI: 10.5061/dryad.mw6m90648
title: Wireless flow-powered miniature robot capable of traversing tubular structures

description: Wireless millimeter-scale robots capable of navigating through
 fluid-flowing tubular structures hold substantial potential for
 inspection, maintenance, or repair use in nuclear, industrial, and medical
 applications. However, prevalent reliance on external power constrains
 their operational range and applicable environments. Alternatives with
 onboard powering must trade off size, functionality, and operation
 duration. Here, we propose a wireless millimeter-scale wheeled robot
 capable of using environmental flows to power and actuate its
 long-distance locomotion through complex pipelines. The flow-powering
 module can convert flow energy into mechanical energy, achieving an
 impeller speed of up to 9595 revolutions per minute, accompanied by an
 output power density of 11.7 watts per cubic meter and an efficiency of
 33.7%. A miniature gearbox module can further transmit the converted
 mechanical energy into the robot’s locomotion system, allowing the robot
 to move against water flow at an average rate of up to 1.05 meters per
 second. The robot’s motion status (moving against/with flow or pausing)
 can be switched using an external magnetic field or an onboard mechanical
 regulator, contingent upon different proposed control designs.
 Additionally, we design kirigami-based soft wheels for adaptive
 locomotion. The robot can move against flows of various substances within
 pipes featuring complex geometries and diverse materials. Solely powered
 by flow, the robot can transport cylindrical payloads with a diameter of
 up to 55% of the pipe’s diameter and carry devices, such as an endoscopic
 camera for pipeline inspection, a wireless temperature sensor for
 environmental temperature monitoring, and a leak-stopper shell for
 infrastructure maintenance.
description: # Wireless flow-powered miniature robot capable of traversing tubular
 structures Supplementary data for Chong Hong et al., "Wireless
 flow-powered miniature robot capable of traversing tubular
 structures", Science Robotics, 9(88), eadi5155, 2024. ## GENERAL
 INFORMATION: 1. Author information: Corresponding authors Name: Wenqi Hu,
 Metin Sitti Institution: Max Planck Institute for Intelligent Systems
 Email: [wenqi@is.mpg.de](mailto:wenqi@is.mpg.de),
 [sitti@is.mpg.de](mailto:sitti@is.mpg.de) 2. Date of data collection:
 2022-2023 3. Geographic location of data collection: Stuttgart, Germany ##
 FILE OVERVIEW: File 1 Name: Figure 2D.xlsx (Date: 2022) File 1
 Description: Data of simulated and experimental mean impeller rotational
 speed with different (i) fin amount and (ii) fin length. File 2 Name:
 Figure 2E.xlsx (Date: 2022) File 2 Description: Data of the simulated mean
 impeller rotational speed with different (i) fin thickness, (ii)
 fin-housing gap, and (iii) fin amount and fin length. File 3 Name: Figure
 2F.xlsx (Date: 2022-2023) File 3 Description: Data of the simulated and
 experimental mean impeller rotational speed, output power, and energy
 conversion efficiency with different (i) flow rates and (ii) load torque.
 File 4 Name: Figure 3C.xlsx (Date: 2022) File 4 Description: Data
 depicting the influence of wheel design parameters of (i) p_d, (ii) p_n,
 and (iii) p_t on average compression force and fluctuation rate η_wheel at
 different compression displacement ∆y. File 5 Name: Figure 3D.xlsx (Date:
 2022) File 5 Description: Data of simulated and experimental (i) average
 compression force F_n and (ii) fluctuation rate η_wheel under different
 compression displacement ∆y for wheels with various values of p_d. File 6
 Name: Figure 4A.xlsx (Date: 2022) File 6 Description: Data of robot
 locomotion speed characterization at different water flow rates in pipes
 with diameters of 10.5 mm, 10.9 mm, and 11.3 mm. File 7 Name: Figure
 6A.xlsx (Date: 2022) File 7 Description: Data of the robot locomotion
 speed with different load length l_load and load diameter d_load. File 8
 Name: Figure S2C.xlsx (Date: 2022) File 8 Description: Data of the
 time-history impeller rotational speed for different fin amounts and fin
 lengths in the simulations. File 9 Name: Figure S2D.xlsx (Date: 2022) File
 9 Description: Data depicting the effect of opening ratio r_open on mean
 impeller rotational speed. File 10 Name: Figure S3C.xlsx (Date: 2022) File
 10 Description: Data of the simulated magnetic gradient force F_g with
 different distance d_m between the two magnets. File 11 Name: Figure
 S4A.xlsx (Date: 2022) File 11 Description: Data of the wheel normal force
 F_n with different p_d for ∆y=0.2 and 0.35 mm. File 12 Name: Figure
 S4B.xlsx (Date: 2022) File 12 Description: Data of the wheel normal force
 F_n with different p_t for ∆y=0.2 and 0.35 mm. File 13 Name: Figure
 S4C.xlsx (Date: 2022) File 13 Description: Data of the wheel normal force
 F_n with different p_n for ∆y=0.2 and 0.35 mm. File 14 Name: Figure
 S6E.xlsx (Date: 2022) File 14 Description: Data of the measured normal
 force F_n with Δx for wheels with different pd under different Δy. File 15
 Name: Figure S6G.xlsx (Date: 2022) File 15 Description: Data of the
 measured normal force F_n for a kirigami wheel and a solid soft wheel at a
 fixed ∆y of 0.35 mm. ## DATA-SPECIFIC INFORMATION Methods for data
 collection or generation and methods used for data processing are detailed
 in Materials and Methods within the associated article. ### DATA-SPECIFIC
 INFORMATION FOR: Figure 2D.xlsx Variable list: Fin amount: Amount of fins
 in the designed impeller Fin length: Length of fins in the designed
 impeller; mm Mean impeller rotational speed: Mean rotational speed of the
 impeller during the steady state; rpm Repetition: Experimentally measured
 mean impeller rotational speed for each repetition; rpm Mean: Mean value
 of the experimental mean impeller rotational speed for 5 repetitions; rpm
 Std (Standard deviation): Standard deviation of the experimental mean
 impeller rotational speed for 5 repetitions; rpm ### DATA-SPECIFIC
 INFORMATION FOR: Figure 2E.xlsx Variable list: Thickness of fins:
 Thickness of fins in the designed impeller; μm Fin-housing gap: the gap
 between the fin and the housing wall; μm Fin amount: Amount of fins in the
 designed impeller Fin length: Length of fins in the designed impeller; mm
 Mean impeller rotational speed: Mean rotational speed of the impeller
 during the steady state; rpm ### DATA-SPECIFIC INFORMATION FOR: Figure
 2F.xlsx Variable list: Flow rate: Mean flow rate within the pipe; m/s
 Standard deviation of flow rate: Standard deviation of the experimental
 flow rate within the pipe; m/s Mean impeller rotational speed: Mean
 rotational speed of the impeller during the steady state; rpm Standard
 deviation of impeller speed: Standard deviation of the experimental mean
 impeller rotational speed; rpm Mean output power: Mean output power of the
 impeller; W Standard deviation of power: Standard deviation of the
 experimental mean output power of the impeller; W Load torque: Load torque
 applied to the impeller; μNm Standard deviation of load torque: Standard
 deviation of the experimental load torque applied to the impeller; μNm
 Repetition: Experimentally measured raw data for each repetition; Mean:
 Mean value of the experimentally measured raw data for 5 repetitions; Std
 (Standard deviation): Standard deviation of the experimentally measured
 raw data for 5 repetitions; ### DATA-SPECIFIC INFORMATION FOR: Figure
 3C.xlsx Variable list: ∆y: Compression displacement of the wheel; mm p_t:
 The thickness-to-diameter ratio of rings in the wheel p_n: The normalized
 quantity of rings in the wheel p_d: The diameter ratio of rings between
 adjacent layers in the wheel Average force F_n: The average compression
 force acting on the wheel during one rotational cycle; mN η_wheel: The
 fluctuation rate of the time-history compression force during one
 rotational cycle; % ### DATA-SPECIFIC INFORMATION FOR: Figure 3D.xlsx
 Variable list: ∆y: Compression displacement of the wheel; mm p_d: The
 diameter ratio of rings between adjacent layers in the wheel Average F_n:
 The average compression force acting on the wheel during one rotational
 cycle; mN η_wheel: The fluctuation rate of the time-history compression
 force during one rotational cycle; % ### DATA-SPECIFIC INFORMATION FOR:
 Figure 4A.xlsx Variable list: Flow rate: Mean flow rate within the pipe;
 m/s Robot velocity against flow: The robot's locomotion velocity when
 moving against the water flow within the pipe; mm/s Robot velocity with
 flow: The robot's locomotion velocity when moving with the water flow
 within the pipe; mm/s ### DATA-SPECIFIC INFORMATION FOR: Figure 6A.xlsx
 Variable list: d_load: Diameter of the cylindrical payload; mm l_load:
 Length of the cylindrical payload; mm Speed: Robot's locomotion speed
 against the water flow when carrying payload; mm/s ### DATA-SPECIFIC
 INFORMATION FOR: Figure S2C.xlsx Variable list: N_fin: Number of fins in
 the designed impeller l_fin: Length of fins in the designed impeller; mm
 Time: Moment in the simulation; s Impeller rotational speed: The
 time-history rotational speed of the impeller in the simulation; rpm ###
 DATA-SPECIFIC INFORMATION FOR: Figure S2D.xlsx Variable list: r_open:
 opening ratio of the housing; % Mean impeller rotational speed: Mean
 rotational speed of the impeller during the steady state; rpm ###
 DATA-SPECIFIC INFORMATION FOR: Figure S3C.xlsx Variable list: d_m: The
 distance between the two magnets; mm F_g: Magnetic gradient force; mN ###
 DATA-SPECIFIC INFORMATION FOR: Figure S4A.xlsx Variable list: ∆y:
 Compression displacement of the wheel; mm ∆x: Horizontal displacement of
 the plate; mm p_d: The diameter ratio of rings between adjacent layers in
 the wheel F_n: The time-history normal force of the wheel; mN ###
 DATA-SPECIFIC INFORMATION FOR: Figure S4B.xlsx Variable list: ∆y:
 Compression displacement of the wheel; mm ∆x: Horizontal displacement of
 the plate; mm p_t: The thickness-to-diameter ratio of rings in the wheel
 F_n: The time-history normal force of the wheel; mN ### DATA-SPECIFIC
 INFORMATION FOR: Figure S4C.xlsx Variable list: ∆y: Compression
 displacement of the wheel; mm ∆x: Horizontal displacement of the plate; mm
 p_n: The normalized quantity of rings in the wheel F_n: The time-history
 normal force of the wheel; mN ### DATA-SPECIFIC INFORMATION FOR: Figure
 S6E.xlsx Variable list: ∆y: Compression displacement of the wheel; mm ∆x:
 Horizontal displacement of the plate; mm F_n: The time-history normal
 force of the wheel; mN ### DATA-SPECIFIC INFORMATION FOR: Figure S6G.xlsx
 Variable list: ∆y: Compression displacement of the wheel; mm F_n: The
 time-history normal force of the wheel; mN