FEATURES
Thin, flexible strips that continuously report their shape
Can be embedded in or placed on objects allowing precision, real-time measurement of shape and shape changes
Low-cost and lends itself to high-volume manufacturing
Unlike traditional sensors which measure a single bend angle, BendShape sensors provide a detailed model of complex curves (e.g., with many bends and/or changing radii of curvature)
Scales from millimeters to meters
Novel sensing technique allows precision operation over time and varying environmental conditions without the need for constant calibration
Reports shape at over one hundred times a second, making them essentially instantaneous in human interface applications. For industrial users or more demanding applications, BendShape can report shape at 1 KHz or more.
The world has curves.
Since the ancient geometers, people have used a straight edge and compass to construct objects and prove mathematical theorems. The addition of measured marks yielded the ruler and protractor, allowed construction of more elaborate creations with finer gradations. Even today, people use linear and angular distances to describe the world and its phenomena because tools to do that are readily available.
Traditionally, complex curves have been measured using a chain of angle sensors. When the angle at the end of the chain is determined by summing the measured angles, it includes the sum of the errors from each individual measurement. Although adding more discrete angle sensors to the chain result in a more detailed measure of a complex curve, it increases the total error.
The BendShape™ sensor is new and different.
It directly measures complex planar curves and does not accumulate angular error. As a result, the BendShape sensor can be used to measure a large number of arc segments, making it ideal for detailed measurement of complex curves and/or curves with many bends.
The availability of this new, inexpensive and precise sensor for curved shapes enables measurement and control of the world in ways that could not be conceived of previously. Curved shapes can now be measured directly, and followed as they change and move. In the past, most of the world’s moving objects were designed using linear or rotary joints, because these are easy to measure. Now, the BendShape sensor makes it easy to measure complex shape and shape changes. As a result, BendShape will open entirely new design options for mechanical systems.
Precision sensing allows precision actuation.
Moving mechanical systems are often designed as a series of rigidly connected, actuated joints that are each measured by an angle sensor. If the mechanism is not rigid, the angle sensors do not represent the true shape. For this reason, systems are frequently over-designed for rigidity.
BendShape reveals the intimate details of system pose. The BendShape sensor’s precision sensing helps close the control loop and allows precise control of system pose, even when the system flexes in complex ways.
BendShape can be integrated into bending actuators. An integrated BendShape sensor/actuator allows commands to create a particular shape, rather than just to trigger an intended amount of movement. And due to BendShape’s speed and accuracy, precise shapes can be created. The BendShape sensor enables devices that morph on the fly, with precise programmable shapes, and even with programmable behaviors, such as “springiness” and “clickability.”
Measure the geometry, not the material.
The BendShape™ sensor works by measuring local curvature along its length, and converting the measurements into the shape of the curve. The sensor comprises two strips that are joined at one end. When laid flat, the electrodes in the sensor line up in a particular way. But when the sensor is curved, the alignment of the electrodes shifts due to the differing radii curves. This shift is a direct measure of the curvature. A detailed model of the curve is derived from numerous shift measurements taken at various places along the strips.
Traditional bend sensors work by measuring the response of a material under bend-induced strain. This material response is often strongly dependent on temperature, humidity, fatigue, and other factors. By contrast, because the BendShape sensor measures geometric change, it has little dependence on the specific materials from which the sensor is made. Directly measuring the tracked quantity just makes more sense than inferring shape change from measured changes in material characteristics.
Changing the shape of things to come.
The ability to dynamically “read” and “write” shape fundamentally changes human interface, wearables, robotics, vehicles, industrial mechanisms, and structural engineering.
As a platform for sensing fluid organic movement, BendShape is ideal for tracking and reconstructing human motion. BendShape sensors can be woven or readily mounted within industrial and athletic apparel, gloves and shoes to track real-time body pose and biometrics like gait and respiration. BendShape sensors will revolutionize gaming in VR and AR, sports performance measurement and rehabilitation therapies.
BendShape is ideal for industrial and structural monitoring to track shape-change of semi-rigid and flexible structures. BendShape can be used to detect and measure shifts in vibration, wear, stress and temperature in applications varying from flexible delivery piping to airfoils (wings, turbines, etc.). The BendShape sensor has excellent stability against age and environmental factors and is easily retrofit on or within existing structures. These characteristics make BendShape an ideal wireless conditional maintenance platform.
The BendShape sensor’s flexibility enables legacy mechanical controls, linkages and systems to be interfaced with modern digital systems. BendShape™ sensors can be positioned to make measurements of a mechanical system more easily than existing sensors. For example, an angle sensor (such as a potentiometer or rotary encoder) might need to be precisely installed near a measured rotation axis, while BendShape sensors require only general proximity to the axis to gain the same information.
Shape memory actuators, electroactive polymers, artificial muscles, and other emerging shape change mechanisms have been slow to gain traction in precision systems due to grossly nonlinear behavior, which produces complex motions that are difficult to sense. BendShape sensors complement these actuation mechanisms, closing the control loop and achieving previously unimaginable precision from such shape-change mechanisms.
The BendShape™ sensor ushers in a new class of “soft” mechatronics and robotics which emulate the fluid curves and supple movement that define organic life. BendShape provides a sensing and actuation platform, built from the ground up, for non-rigid structures.
