Systems and methods for origami-inspired wearable robots for trunk support
View Patent ↗Systems and methods for a wearable “exo-shell” to improve the gait of elderly people during obstacle avoidance tasks are disclosed. With payload and energy expenditure as a main focus of this design, the present system leverages switchable, passive systems, in combination with lightweight materials that minimize additional metabolic costs, while remaining as “transparent” to the user as possible when inactive.
1 . An origami-inspired wearable device for trunk support, comprising:
a body configured for mounting along a back of a user, the body including:
a base, and
a plurality of triangle segments formed via laminate fabrication and serially connected over the base, wherein each triangle segment of the plurality of triangle segments is fold-formed from a laminated stack including at least one rigid outer layer and a flexible hinge layer configured to permit rotation at a joint between adjacent triangle segments;
a sensor assembly including one or more sensors positioned along the body that measure joint angles associated with the plurality of triangle segments;
a brake system configured to stiffen lockable joints of the plurality of triangle segments, including
a belt engaged to each of the plurality of triangle segments, and
a motorized clamp that applies forces to the belt; and
a microcontroller positioned along the base of the body that engages the motorized clamp in response to an anticipated state change computed from the joint angles to stiffen the lockable joints of the plurality of triangle segments and provide support to the user.
2 . The device of claim 1 , wherein a proximal end of the body aligns along a waist of the user and a distal end of the body is mounted between shoulders of the user to improve a gait of the user during obstacle avoidance tasks.
3 . The device of claim 1 , wherein outer faces of each of the plurality of triangle segments serve as simple joint limits to restrict motion to a predetermined range corresponding to dimensions and a base connection point.
4 . The device of claim 1 , wherein each of the plurality of triangle segments comprises a plurality of layers assembled during laminate fabrication, including outer layers defining rigid material, followed by layers of adhesive, a middle flexible layer to form a living hinge, and a flexible circuit layer for mounting and connecting the one or more sensors to power and communication with the microcontroller.
5 . The device of claim 1 , wherein the brake system applies a minimum required braking force calculated by the microcontroller to lock movement of the lockable joints based on a tensile force in each lockable joint.
6 . The device of claim 1 , wherein the brake system applies a minimum required braking force in the belt through a constrained minimization formulation calculated by the microcontroller and based on the measured joint angles associated with the plurality of triangle segments.
7 . The device of claim 1 , wherein the body further comprises a quadrilateral end effector connected serially to the plurality of triangle segments and positioned distal from the body, the quadrilateral segment comprising:
a first vertex and a second vertex defined opposite the first vertex and configured for translational motion in response to tensile and external forces.
8 . The device of claim 7 , wherein the brake system applies a calculated minimum required tension in the belt through a constrained minimization formulation based on the measured joint angles associated with the plurality of triangle segments and the position of the quadrilateral end effector.
9 . The device of claim 1 , wherein the lockable joints provide movement in at least one degree of freedom.
10 . The device of claim 1 , wherein the brake system further comprises a tension mechanism that maintains tension in the belt to minimize backlash.
11 . The device of claim 10 , wherein the tension mechanism includes a spring-loaded pulley.
12 . An origami-inspired wearable device for trunk support, comprising:
a body defining a serial chain of lockable joints, the body comprising a plurality of segments coupled by the lockable joints, wherein at least one of the segments is fold-formed from a laminated stack including at least one rigid outer layer and a flexible hinge layer configured to permit rotation at one of the lockable joints;
one or more sensors that measure joint angles associated with the lockable joints;
a brake system mechanically coupled to the lockable joints, the brake system including at least one flexible belt engaged with the body and a clamp configured to selectively apply a normal clamping force to the belt to increase friction and thereby stiffen at least one of the lockable joints; and
a microcontroller that engages the brake system to stiffen the lockable joints in response to an anticipated state change as determined using the joint angles.
13 . The device of claim 12 , wherein the body includes a base and plurality of segments, the plurality of segments including serially connected segments and at least one segment coupled to the base.
14 . The device of claim 13 , wherein each of the plurality of segments is comprised of a laminate comprised of one or more outer layers, an adhesive, a middle layer defining a hinge, and a flexible circuit layer for mounting and connecting the one or more sensors.
15 . The device of claim 12 , wherein the brake system includes a plurality of belts attached to each moving segment of the plurality of segments, and a lower portion of the plurality of belts is clamped to a base of the body via self-aligning brake pads.
16 . The device of claim 12 , wherein the brake system further comprises a tension mechanism including a spring-loaded pulley that maintains tension in a belt of the brake system to minimize backlash.
17 . The device of claim 12 , wherein the brake system is configured to stiffen the lockable joints by applying a normal clamping force to one or more flexible, sliding sheet-based belt layers to increase friction between the belt layers and resist relative sliding motion that would otherwise permit joint movement.
18 . A method of making a wearable device for trunk support, comprising:
forming a laminate, comprising:
layering a flexible hinge material and a flexible circuit with an outer rigid layer;
embedding a sensor within the flexible circuit;
(i) cutting away a portion of the laminate
(ii) folding the portion to form a triangle segment;
repeating (i)-(ii) a predetermined number of times to form a plurality of triangle segments, wherein forming the plurality of triangle segments includes fold-forming the portion from at least one rigid outer layer and a flexible hinge layer of the laminate to accommodate rotation at a joint between adjacent triangle segments of the plurality of triangle segments;
connecting serially the plurality of triangle segments to form lockable joints such that a circuit of each triangle segment is connected to each adjacent segment;
providing a base including a housing comprising a motor assembly and a motorized clamp;
connecting the plurality of triangle segments to the base with at least one belt, wherein the belt is configured to retract and extend from the motor assembly to lock and unlock the joints; and
mounting a microcontroller along the base and electrically connected with the motor assembly, the motorized clamp, and the flexible circuit layer of each triangle segment.
19 . The method of claim 18 , further comprising providing a moveable pulley positioned along the base wherein the moveable pulley is configured to maintain tension in the belt.
20 . The method of claim 18 , further comprising configuring the microcontroller to engage the motorized clamp in response to an anticipated state change computed from joint angles measured by the sensor to stiffen the lockable joints of the plurality of triangle segments and provide support to a user.