Soft-Bodied Force Sensor Using Hall Effect Sensors and Magnets
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Solution Overview
Problem
Conventional robotic sensing methods rely on rigid structures, which are inadequate for accurately modeling and detecting deformations and forces in soft or resilient materials, often resulting in imprecise positioning and potential damage to objects due to the need for physical contact and sensitivity drift issues.
Innovation Solution
A soft-bodied force sensor using a deformable base with Hall effect sensors and rare-earth permanent magnets to detect curvature and compression, allowing for non-contact, high-accuracy positioning and force measurement by calculating magnetic flux density changes, enabling precise robotic movement and object interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional rigid structures are used for robotic sensing, then positioning precision is maintained through low tolerance, but the system cannot accurately model or detect deformations in soft or resilient materials
Solution Approach 1:
The patent replaces conventional mechanical strain measurement systems with a magnetic field-based sensing system. Hall effect sensors detect changes in magnetic flux density caused by deformation of the resilient base, eliminating the need for mechanical strain gauges and their associated drift and tolerance issues. This substitution enables accurate deformation detection in soft materials while maintaining positioning precision.
Solution Approach 2:
The patent changes the measurement parameter from mechanical strain to magnetic flux density. By embedding magnets in the resilient base and using Hall effect sensors to detect magnetic field changes, the system transforms physical deformation into measurable magnetic parameter variations. This parameter change allows accurate modeling of soft material deformation without the limitations of conventional mechanical sensing.
2Reliability
If physical contact is made to detect an object, then object presence is confirmed, but imprecise forces can damage the object
Solution Approach 1:
The patent replaces mechanical contact-based detection with a magnetic field-based sensing system. The Hall effect sensors detect object presence and deformation through magnetic flux changes without requiring physical contact or application of force. This eliminates the harmful mechanical forces that could damage fragile objects while maintaining reliable detection capability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the sensor and the object. Instead of direct mechanical contact, the Hall effect sensors detect objects through changes in the magnetic field generated by embedded magnets. This intermediary field allows detection and force measurement without physical contact, preventing damage to fragile objects.
3Measurement precision
If strain gauges are used for sensing, then deformation can be measured, but the system is subject to drift and dynamic artefacts
Solution Approach 1:
The patent replaces mechanical strain gauges with a magnetic field-based sensing system using Hall effect sensors. This substitution eliminates the drift and dynamic artefacts inherent in resistive strain gauges, as magnetic field measurements are not subject to the same material response issues. The system maintains deformation measurement capability while significantly improving sensing stability and reliability.
4Measurement precision
If rigid articulated members are used for positioning, then precise positioning information is achieved, but the system cannot model curvature and deformation of soft members
Solution Approach 1:
The patent changes the modeling parameter from rigid body translation to magnetic flux density variation. By using Hall effect sensors to detect changes in the magnetic field caused by deformation of the resilient base, the system can accurately model curvature and deformation of soft members. This parameter change enables the representation of continuous deformation fields that cannot be captured by conventional rigid body kinematics.
Solution Approach 2:
The patent uses a resilient base (flexible shell) to which magnets are attached, allowing the structure to deform while maintaining structural integrity. The Hall effect sensors embedded in or near this flexible base detect the deformation through magnetic field changes. This approach enables accurate positioning and deformation modeling of soft members while maintaining the precision needed for robotic control.
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
The solution provides a compact, accurate, and dynamic response for robotic systems, capable of distinguishing between different objects and forces without physical contact, enhancing precision and reducing the risk of damage, by modeling robotic movements as curvature changes in a kinematic chain of segments.
Implementation Method 1
Hall effect sensors coupled to rare-earth permanent magnets in a deformable base allow sensing of surface curvature and compression against grasped objects
Implementation Method 2
Other uses and applications using modeling and detection of magnetic flux density received by a Hall effect or other magnetic sensor may be employed
Data Source
AI summary
A robotic sensing and touch apparatus detects gradual deformations in a resilient surface, in contrast to conventional rigid member displacement. Hall effect sensors coupled to rare-earth magnets in a deformable base allow sensing of surface curvature and compression against grasped objects. The deformable base, such as a silicone mold or other resilient encapsulation, fixes a magnetic source and an opposed Hall effect sensor. Calibration of a received magnetic field is defined by a sensor element voltage in an “at rest” (undeformed) state, and at successive degrees of deformation resulting from compression of the deformable base that draws the magnet in different orientations relative to the Hall effect sensor. An array of magnet and sensor element pairs allows relative sensing over an area for detecting curvature of a translated or articulated member, or engagement with a curved surface.