Tactile Display Nodule Using Granular Jamming for Palpation
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Solution Overview
Problem
Current tactile display devices for medical palpation simulations fail to maintain the shape of a nodule while varying its stiffness, which is crucial for differentiating between normal and affected lumps, especially when their dimensions are the same, and they do not provide a realistic sensation of touch similar to human palpation.
Innovation Solution
A tactile display device using granular jamming technology with pneumatic actuation, featuring a hemispherically combined nodule with distinct material properties and thicknesses for the contact and actuation portions, allowing for variable stiffness without altering the nodule's dimensions, mimicking the sensation of palpating real tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional haptic devices or pneumatic simulators are used to vary tissue stiffness, then stiffness variation is achieved, but the shape of the nodule cannot be maintained while varying stiffness
Solution Approach 1:
The nodule is segmented into multiple independent inflatable chambers, each capable of being inflated or deflated independently. This segmentation allows different regions of the nodule to have different stiffness levels while maintaining the overall spherical shape, as each chamber can be controlled separately to preserve the external contour.
Solution Approach 2:
Different regions of the nodule are given different local stiffness properties through selective inflation of individual chambers. The system can create localized stiff or soft regions within the nodule while maintaining the overall shape, enabling realistic simulation of heterogeneous tissue properties without distorting the external form.
2Adaptability or versatility
If granular jamming is used to simulate tissue stiffness, then variable stiffness feedback is achieved, but the shape of the mass becomes deformable
Solution Approach 1:
A flexible outer shell or membrane encloses the granular material, maintaining the spherical shape of the nodule. The shell is sufficiently flexible to allow internal granular rearrangement for stiffness variation but rigid enough to preserve the external geometry, thus decoupling shape maintenance from stiffness control.
Solution Approach 2:
The flexible shell acts as an intermediary between the granular jamming mechanism and the external environment. It transmits the stiffness variations generated by granular jamming to the user's finger while maintaining a stable spherical shape, serving as a mediator that separates shape maintenance from stiffness modulation.
3Measurement precision
If a tactile display device provides variable stiffness sensation, then diagnostic accuracy is improved, but the device complexity increases
Solution Approach 1:
The tactile display device integrates multiple functions into a single unit: it can vary stiffness, maintain shape, provide tactile feedback, and simulate different tissue types. The inflatable chamber system serves multiple purposes simultaneously - controlling stiffness, maintaining geometry, and providing realistic tactile sensation - thereby reducing overall system complexity despite the enhanced diagnostic capability.
Solution Approach 2:
The device creates a simplified yet realistic copy of actual tissue nodules with controllable stiffness properties. By using inflatable chambers or granular jamming within a constrained shell, the system replicates the essential tactile characteristics of real tissues without requiring complex biological samples, achieving diagnostic accuracy through controlled physical analogs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables physicians to accurately identify differences in lump stiffness and severity, even when lumps have the same dimensions, providing a near-realistic tactile experience for improved diagnostic training and telemedicine applications.
Implementation Method 1
The plurality of granules are used in a granular jamming implementation within the nodule, in which the displacement of the plurality of granules differs depending on the pressure value within the nodule.
Implementation Method 2
When a vacuum is applied to the nodule, the shape of the nodule is maintained while the stiffness of the nodule increases due to the granular jamming.
Implementation Method 3
a pneumatic control unit that removes a portion of air within the nodule to actuate a granular jamming mechanism that increases a stiffness of the nodule
Data Source
AI summary
A tactile display device including a nodule having variable stiffness under a surface to provide a near-real feeling of palpation for a physician. The device utilizes granular jamming technology using pneumatic actuation to control a nodule that maintains its shape while allowing the modulation in stiffness. The nodule includes two hemispheres, a contact portion and an actuation portion, forming a sphere. The contact portion and the actuation portion include different thicknesses and/or materials, while the dimensions of the dimensions of the nodule are maintained. As such, a physician can utilize the device to identify the difference between a normal lump and an affected lump even if the shape of each lump appears to be the same. With the tactile display device, due to the different levels of stiffness, a physician can detect the severity of the lump.