Design of an Electro-pneumatic Control System for Soft Robotic Applications in Medicine and Industry
John Wischmeyer
Advisors: David Myszka, Ph.D & Andrew Murray, Ph.D
Department of Mechanical & Aerospace Engineering
Objective: To develop programmable “Smart Nozzles” for coolant distribution in machining processes.
Smart Nozzle Anatomy
DLP Print Quality Concerns:
External leaking to atmosphere Internal leaking between chambers
Assembly Components
Barbed adapters: Mesh with internal walls of connector tubes Mounting plate: Provides support and assists with pressure seal Adapter brace: Bolted to mounting plate, forces barbed fittings to stay wedged within soft robot Top Cap: Bolted to mounting plate, forced soft robot to remain in contact with barbed adapters
Why Soft Robots?
Naturally compliant, “ safe interaction with humans, manipulating and grasping fragile objects ” [1] Actuators with high strength-weight ratio
Applications in various industries:
Health care: Exosuits, artificial organs Space exploration: Biologically-inspired actuators Automation: Product manufacturing & assembly
Project Objective
Pneumatic “Smart Nozzles”, capable of directing coolant flow on machining tools
Theoretical Background
Finite Element Analysis of Smart Nozzle variations Performance predicting based on design geometry, material properties, and supplied air pressure
Experimentation
Quality air pressure control is the foundation for all soft robot projects
MATLAB/Arduino
USB webcam visual feedback, tracks marker centroid MATLAB GUI: user-controlled slider target Arduino computes: Error = Centroid - Slider values
Three States:
Error < (-1)*Tolerance → increase pressure Error > (+1)*Tolerance → decrease pressure Error ≤ abs(Tolerance) → hold pressure constant
Future Work
Continued SOLIDWORKS modeling of new prototypes Expanding MATLAB GUI research, multi-object detection and tracking
References
[1] G. Alici, “Softer is harder: What differentiates soft robotics from hard robotics?,” MRS
Advances, vol. 3, no. 28, pp. 1557–1568, 2018.
[2] “Chip Rite General Purpose Coolants,” KOOLRite . [Online]. Available: https://www.koolrite.com/machine-cutting-coolant/cnc-coolant/chip-rite/. [Accessed: 12-Apr-2023].
[3] Author Susan Woods Susan Woods served as a Contributing Editor for Cutting Tool Engineering magazine. and S. Woods, “Cool tool,” Cutting Tool Engineering . [Online]. Available: https://www.ctemag.com/news/articles/cool-tool. [Accessed: 12-Apr-2023].
Figure 4: Exploded View of “Taurus” Mounting Assembly
Figure 1: (a.) Loc-line Hose Assembly [2],
(b.) Metallic Coolant Line Platform [3]
Figure 2: SolidWorks Finite Element Analysis of ABAQUS and 3-Chamber Actuators
Figure 3: Section View of 2-Chamber “Taurus” Smart Nozzle
Figure 5: (a.) Pressure Mitigation Device – Top View, (b.) MATLAB GUI Slider Control
CAD modeling and 3D printing go hand-in-hand, reduce part production time to a fraction of how long it takes for molding to create the same part
Pressure Control: Now a question you may be asking yourselves is: “If the cells are all connected to the same air supply, how can we independently adjust the pressure inside each cell?” The answer: Proportional control valves.
Proportional control valves - Digital to analog convertor, reads electrical signal from microcontroller, opens valve by a corresponding amount.
Microcontroller – by implementing an Arduino and multiple pressure control valves, we will essentially be able to control the pressure distribution in the pneumatic cushion from a laptop