PATENT Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT1 MODULAR ORIGAMI SHAPE-MORPHING SOFT EXOSKELETAL LEGGED ROBOT RELATED APPLICATION [0001] This application claims priority to US Provisional Patent Application Number 63/535,639, filed August 31, 2023, and incorporated herein by reference in its entirety. BACKGROUND [0002] One area of significant societal impact that robots have the potential to realize is with search and rescue operations. Another significant area is high-value asset inspection. To be effective, robots not only need to traverse challenging, complex rubble from collapsed structures, but also need the ability to effectively ingress and egress through small crevices. To date, snake-like serpentine robots have proven most successful practically in these scenarios. However, they are still inadequate due to their fixed aspect ratios. For example, their long slender bodies can enter crevices but get stuck while turning in them. The majority of legged robots demonstrating robust locomotion capabilities on uncertain terrains are the size of small mammals or larger, and therefore, still too large for these applications. Miniature robots demonstrating locomotion capabilities of their larger counterparts are still limited by their largest body dimension for crevice traversal. Miniature soft robots are an obvious solution to tackle this problem. However, their reliance on material properties to achieve compliance limits their overall performance in terms of speed, payload and onboard power. [0003] The majority of robots, across all size scales, still maintain fixed body shapes (typically cuboidal) and are therefore unable to exploit the benefits of shape adaptation for complex terrain locomotion. One reason for this, especially on a smaller scale, is the increasing difficulty of design and fabrication associated with miniaturization. Another reason is the enhanced actuation and control efforts associated with a higher number of articulated degrees-of-freedom (DoF) in the body. SUMMARY [0004] The capability of body deformation further enhances the reachability of these small robots in cluttered terrains similar to those of insects and soft arthropods. Motivated by this concept, compliant legged articulated robotic insect (the robot), an insect-scale 2.59 g LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT quadrupedal robot capable of body deformation is presented, and manufactured using laminate fabrication and assembled using origami pop-up techniques. To enable locomotion in multiple shape configurations, a novel body architecture includes modular, actuated leg mechanisms. Overall, the robot has eight independently actuated degrees-of-freedom (two per modular leg unit) driven by custom piezoelectric actuators, making it mechanically dexterous. Herein, open-loop robot locomotion at multiple stride frequencies (1–10) Hz is characterized using multiple gaits (trot, walk, etc.) in three different fixed body shapes (long, symmetric, wide) and the robot’s capabilities are illustrated. Finally, preliminary results of locomoting with a compliant body in open terrain and through a laterally constrained gap, a novel capability for legged robots, is demonstrated. [0005] A body of the robot has programmable distributed compliance that allows the robot to squeeze into difficult to access spaces. The modular origami based unit enables scalable design. Possible uses for the robot includes: 1. Search and Rescue (e.g. earthquakes/ rubbles) 2. High Value Asset Inspection and Maintenance (e.g. Rolls-Royce, ENEL) 3. Environmental Monitoring 4. Surgical robots (e.g., by further miniaturization). [0006] No other robots at this scale have demonstrated the ability of significant body deformation/compression by taking advantage of body compliance. [0007] In certain embodiments, the techniques described herein relate to a modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance; wherein the flexure has a flexural strength selected to allow the body to morph in response to a force resulting from self- propelled motion of the robot into a constricted environment. [0008] In certain embodiments, the techniques described herein relate to a modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0009] In certain embodiments, the techniques described herein relate to a leg module for a modular origami shape-morphing soft exoskeletal legged robot, including: a spherical five-bar (SFB) linkage that interlinks the two and couples to a leg output with at least two degrees-of-freedom; two actuators that mechanically couple with a lift input and a swing input of the SFB linkage; and a mechanical ground formed between the actuators and the SFB linkage. BRIEF DESCRIPTION OF THE FIGURES [0010] FIG.1 is a perspective view illustrating one example modular origami shape- morphing soft exoskeletal legged robot, in embodiments. [0011] FIG.2A is a system diagram illustrating the robot of FIG.1 in further example detail, in embodiments. [0012] FIG.2B shows example detail of mechanical coupling between the leg modules and the flex section of the robot of FIGs.1 and 2A, in embodiments. [0013] FIGs.3A-D are schematics illustrating example fabrication of the leg mechanism of FIG.1 from a laminate sheet, in embodiments. [0014] FIG.4 is a perspective schematic illustrating the leg mechanism of FIGs.3A- C in further example detail, in embodiments. [0015] FIG.5 shows the leg mechanism of FIG.4 in further example detail, illustrating coupling of the lift linkage and the swing linkage to the SFB linkage by crank- slider mechanisms, in embodiments. [0016] FIG.6 is a side view of the leg mechanism of FIG.4, in embodiments. [0017] FIG.7 is a plan view of the leg mechanism of FIG.4, in embodiments. [0018] FIGs.8A and 8B illustrate characterization of the leg mechanism of FIG.4, in embodiments. [0019] FIGs.9A, 9B, and 9C are schematic plan views illustrating example body morphing of the robot of FIG.1, in embodiments. [0020] FIG.10 is a schematic illustrating example conformance of the robot of FIG.1 moving through an environment with a lateral constraint, in embodiments. [0021] FIG.11 is a composite image of five plan view images captured during a compliance demonstration where the robot of FIG.1 moves through a lateral constraint, in embodiments. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0022] FIG.12 is a composite image of four plan view images captured during a demonstration of the robot of FIG.1 moving in three directions without turning, in embodiments. [0023] FIG.13 is a composite image of five plan view images captured during a demonstration of the robot of FIG.1 combining body morphing, as illustrated in FIG.11, with omnidirectional movement, as illustrated in FIG.12, to maneuver itself through a 90° confinement corner, in embodiments. [0024] FIG.14 is a perspective view of a robot that is a forerunner of the robot of FIG.1. [0025] FIG.15 is a schematic illustrating one example robot with six leg modules and six flex sections that are interconnected to form a body that is a closed kinematic chain, in embodiments. [0026] FIG.16 is a schematic illustrating one example robot with eight leg modules and eight flex sections that are interconnected to form a body that is a closed kinematic chain, in embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS [0027] FIG.1 is a perspective view illustrating one example modular origami shape- morphing soft exoskeletal legged robot 100, in embodiments. Robot 100 has four leg modules 104 where pairs of adjacent leg modules 104 are interconnected by a flex section 105. For example, a first and second leg module 104 are interconnected by a first flex section 105, the second leg module 104 and a third leg module 104 are interconnected by a second flex section 105, the third leg module 104 and a fourth leg module 104 are interconnected by a third flex section 105, and the fourth leg module 104 and the first leg module 104 are connected by a fourth flex section 105 to form a body 102 of robot 100. Each leg module 104 includes an independently articulated leg 106, where leg modules 104 cooperate to provide locomotion of robot 100. A key feature of robot 100 is the use of leg modules 104, which is atypical of robots of this scale. Advantageously, leg modules 104 are manufactured without concern of position on the robot. Thus, the leg modules 104 may be independently manufactured and characterized prior to integration into body 102., and the complexity of building and testing different leg designs is avoided. A further advantage of leg module 104 is that it allows easy repair and replacement of degrading individual appendages of robot 100 thereby making maintenance of robot 100 easier that other prior art robots of this scale. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0028] Each leg module 104 forms a flat, rigid side 103. Each flex section 105 includes two flat rigid panels 109 that are joined by a single long flexure 114 that allows a single degree-of-freedom in a lateral plane between the two rigid panels 109. These flexures collectively provide articulated morphology of body 102 for lateral body compliance. Particularly, leg modules 104 and flex sections 105 connect to form body 102 as a closed kinematic chain that allows body 102 to morph and pass through a lateral constraint that is smaller than a width of robot 100. Single long flexure 114 is formed by the flexible layer of the laminate. The flexible layer is selected to have a flexural strength that allows morphing of body 102 in response to external forces resulting from self-propelled motion of robot 100 into a constricted environment and such that body 102 returns to a non-morphed state when the external forces are removed. A geometry of the flexures 114 within body 102 provide distributed compliance of the body. The experimentally determined range of bending stiffness for the body joints for effective walking is in the range of 2.1×10
-6 Nm to 19×10
-6 Nm based on current morphology. [0029] In the example of FIG.1, robot 100 is symmetrical (e.g., square) from a plan perspective when there are no external forces (e.g., when robot 100 unconstrained). That is, a width and a length of robot 100 are substantially equal when robot 100 is in a natural state and unconstrained. Advantageously, robot 100, in at least one embodiment, is capable of: (a) compressing to two-thirds of its body length through an external force of a constraint, and (b) compressing to two-thirds of the body width through the external force. [0030] Each leg module 104 includes a lift actuator 108(1) and a swing actuator 108(2) (see FIGs.2A, 2B, 4, and 6 for further detail) that drive a leg mechanism 107 of leg module 104. Actuators 108 are controlled to manipulate leg 106 in at least two degrees-of- freedom (e.g., lift and swing). Actuators 108 mechanically couple with a spherical five-bar (SFB) linkage 110 of leg mechanism 107 that in turn couples with leg 106. Actuators 108 may be independently controlled to provide a lift force and a swing force to SFB linkage 110 and thereby cause leg 106 to provide lift of body 102 and provide a swing movement that maneuvers body 102. One bar of SFB linkage 110 is a mechanical ground formed by a portion of rigid side 103 of body 102. A second bar of SFB linkage 110 mechanically couples to leg 106. Actuators 108 are controlled to apply forces to SFB linkage 110 and thereby cause leg 106 to move in a desired gait. Leg mechanism 107 is shown in further detail in FIGs.4–7 and described in detail below. [0031] In certain embodiments, actuators 108 are piezoelectric actuators that are driven by an electrical charge that causes the actuator to flex and apply a force to SFB LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT linkage 110. Actuators 108 are controlled independently to cause a desired movement of leg 106 relative to body 102. For example, through cooperation of both actuators 108, leg 106 is controlled to raise, swing in a forward direction, lower, and then swing in the opposite direction causing robot 100 to move relative to the surface on which robot 100 is operating. [0032] FIG.2A is a system diagram illustrating robot 100 of FIG.1 in further example detail, in embodiments. FIG.2B is a schematic shows a portion of robot 100 of FIG.1 with power PCBs 112 omitted to illustrate connectivity of flex sections 105 with rigid sides 103 in further example detail. [0033] A controller 202 includes a processor 204, memory 206, a plurality of drivers 208(1)-(8), a power source 210, and wires 212 that couples drivers 208 with actuators 108. Controller 202 may include one driver 208 for each actuator 108 of robot 100, for example. In the example of FIG.2A, controller 202 is external to robot 100 and connects via tether wires 212. However, controller 202 may be incorporated within body 102, based on the intended application of robot 100. Further, although power source 210 is shown internal to controller 202, power source 210 may be external to controller 202. [0034] Drivers 208 are electronic circuits coupled with power source 210 and controlled by processor 204 to generate electrical signals to control operation of actuators 108. Memory 206 stores software 214 including machine-readable instructions that, when executed by processor 204, cause processor 204 to control drivers 208 to actuate legs 106 and cause robot 100 to move in a desired direction. For example, 214 may include a gait algorithm 216 that controls drivers 208 to generate control signals via wires 212 that cause leg modules 104 to move legs 106 to provide desired maneuvering of robot 100. Gait algorithm 216 may control drivers 208 to cause robot 100 to move at a desired speed in one of a forward direction, a reverse direction, a first sideways direction, and an opposite sideways direction, as well as combinations thereof. Gait algorithm 216 may also control drivers 208 to cause robot to turn, both with and without lateral motion. Gait algorithm 216 may control drivers 208 to cause robot 100 to move in other manners without departing from the scope hereof. For example, gait algorithm 216 may control drivers 208 to cause robot 100 to move in diagonal directions. Controller 202 may implement other functionality without departing from the scope hereof. [0035] FIG.2B shows example detail of mechanical coupling between leg modules 104 and flex section 105 of robot 100 of FIGs.1 and 2A, in embodiments. Rigid panel 109 of flex sections 105 rigidly couples with rigid side 103 of leg module 104 and is braced by internal supports 220 and 222 as shown. Accordingly, rigid side 103 and two flat rigid panels 6 LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT 109 do not flex relative to one another. However, each adjacent pair of leg modules 104 may change position relative to one another via single long flexure 114. [0036] FIGs.3A–D are schematics illustrating example fabrication of leg mechanism 107 of FIG.1 from a laminate sheet, in embodiments. FIGs.3A-D are best viewed together with the following description. [0037] Each leg module 104 of robot 100 may be similarly formed. A planar laminate stack 300 is precut (e.g., using a femtosecond laser micromachine in at least some embodiments) and components of SFB linkage 110 are folded (FIG.3B) into the correct orientation and integrated (FIG.3C) with actuators 108 and a power printed circuit board (power PCB) 112 to form leg module 104. Leg modules 104 are then assembled with flex sections 105 to form body 102 of robot 100. [0038] Leg modules 104 and flex sections 105 are formed, at least in part, from a laminate that includes at least two rigid layers and at least one flexible layer. In certain embodiments, the laminate is formed of two outer rigid structural layers of Carbon fiber (100^m thickness and a 0-90-0 fiber orientation), a center flexible layer of Kapton Polyimide film (25^m) for flexures, and two adhesive layers of DuPont Pyralux FR1500 (13^m per layer). The laminate is then processed the laser micromachine to form parts that may be folded and/or coupled together. As shown in FIG.3A, the laser micromachine may cut through the laminate to form apertures and to separate individual parts and may remove both outer layers (e.g., by ablation) to leave a flexible joint between two part. Flex sections 105 are similarly processed from a laminate sheet, where single long flexure 114 is formed through ablation of both the inner layer and outer layer of the laminate to leave the inner layer to form the flexure. The laser micromachine is also controlled to form a fold between two portions of the laminate using a combination of cuts and ablations. A width of the combined cut and ablation allows a first part to fold flat against a second adjoining part to form a double thickness section for additional stiffness. FIG.3B illustrates a first fold that forms a stiffened ground 302 and a second fold that forms a stiffened swing input 304 to SFB linkage 110. FIG.3D is an alternative perspective view of the folded laminate illustrating stiffened lift input 306 to SFB linkage 110. [0039] FIG.4 is a perspective schematic illustrating leg mechanism 107 of FIGs.3A- C in further example detail, in embodiments. Particularly, FIG.4 shows example coupling of SFB linkage 110 of FIGs.1 and 3B with lift actuator 108(1) and swing actuator 108(2). SFB linkage 110 is designed and formed such that actuators 108 are positioned vertically and parallel to one another within robot 100. This improves the overall compactness of leg 7 LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT mechanism 107, facilitating assembly into an insect-scale robot while maintaining sufficient internal space to permit significant changes in aspect ratio of body 102. To enable this modification, a number of small design changes were made to the SFB linkage 110 as compared to prior art SFB designs, by adhering to fabrication and assembly considerations for robot 100. One significant change is a reduction in the total number of layers in the laminate from 11 to 5 by merging the transmission sub-laminate and the chassis sub-laminate into the same layers. This modification uses half the raw materials required in prior art designs, reduces the mass of SFB linkage 110, and reduces the number of machining cycles required for manufacturer. [0040] In the example of FIG.4, a mechanical ground 402 is formed by part of body 102 (e.g., rigid side 103) and mechanical ground 402 interlinks with mechanical grounds 404 and 406 for actuators 108(1) and 108(2), respectively, via a mounting frame 230 of actuators 108. For example, mechanical grounds 404 and 406 may be part of mounting frame 230, which is securely mechanically coupled with rigid side 103. Mechanical ground 402, 404, and 406 may be doubly reinforced to minimize transmission losses. In certain embodiments, mounting frame 230 is an origami-style foldable flexible electronics board that was developed to provide the structural integrity required to hold actuators 108 in place relative to the leg transmission, and to have flexible joints with conductive traces to ease the assembly process of leg module 104. In certain embodiments, the layer structure of mounting frame 230 is FR4 fiberglass (127^m) as the structural layer, FR1500 (13^m) as adhesive, and a Copper clad Kapton prestacked layer of Kapton (25^m), adhesive (25^m) and copper (17.5^m). The rigid structural layer is cut into shapes for the side walls and structural components with tabs on the side to interlock with the carbon fiber of the leg transmission. Using the custom laser micromachine (e.g., 6D Lasers), copper is ablated to leave traces on the bare Kapton film that connect central tether wires to each actuator 108. For mounting frame 230, the folding joints were 300^m wide, allowing for a folding radius that results in minimal strain tearing of the copper layer. Mounting frame 230 may also provide electrical connections from 4 pins of a pin header (each connected to a shared ground, a shared high voltage bias, a lift voltage signal and a swing voltage signal respectively) to the top of the leg module to allow for ease of connecting wires during testing. [0041] SFB linkage 110 is formed to cross-link dynamic movement from actuators 108(1) and 108(2) via lift linkage 408 and swing linkage 410, respectively, to leg 106, which may be glued to a lowest point of SFB linkage 110. A first end (receiving lift input) of SFB linkage 110 joins mechanical ground 402 at a horizontal axis of rotation 412 and the other LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT end (receiving swing input) of SFB linkage 110 joins mechanical ground 402 at a vertical center of rotation 414. [0042] FIG.5 shows leg mechanism 107 of FIG.4 in further example detail, illustrating coupling of lift linkage 408 and swing linkage 410 to SFB linkage 110 by crank- slider mechanisms 502 and 504, respectively, in embodiments. Both crank-slider mechanisms 502 and 504 are actuated as close as possible (e.g., at a distance of s
i 506 and l
i 508) to center of rotations 412 and 414, respectively, to minimize off-axis bending, which was an issue with prior designs. [0043] Swing actuator 108(2) primarily controls the swing movement (e.g., protraction and retraction) of leg 106, and lift actuator 108(1) directly influences both (a) lift motion (e.g., elevation–depression) and expansion motion (e.g., adduction–abduction) of leg 106. In the prior art of other small legged robots, the expansion motion has largely been ignored, since the expansion motion minimally influences overall locomotion performance in open terrains; however, this motion may become critical when navigating through laterally confined terrains. [0044] FIG.6 is a side view of leg mechanism 107 of FIG.4, in embodiments. FIG.7 is a plan view of leg mechanism 107 of FIG.4, in embodiments. FIGs.6 and 7 are best viewed together with the following description. [0045] Leg mechanism 107 is designed to amplify the displacement output of the lift and swing actuators 108(1) and 108(2) (e.g., į
al and į
as, respectively), while reducing the force output in each of the directions. A primary guiding principle is to have sufficient force output to support the weight of robot 100 on two legs 106 in the vertical direction while still achieving stride lengths comparable to a similarly sized prior art robots. To simplify our design, we chose the identical amplification joint distance s
i and l
i to result in the highest transmission ratios to meet the aforementioned criteria in swing (
^^ ൌ ^
ை^/^
^) and lift (
^^ ൌ ^
ை^/^
^). [0046] To improve the transmission output performance (plastic deformation due to off-axis forces), both the swing and lift lever arms ratios were reduced relative to CLARI. Transmission ratio in the lift direction was designed to TRatio,L = 12.5, with the lift input connection to the SFB being l
i = 500^m. The distance from the leg tip to the transmission joint center is referred to as l
d and s
d for the lift and swing respectively. The lift is biased towards having larger force and leg stiffness to support the body mass and additional payload. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT
[0048] The leg tip is calculated to be placed 6.25mm below the transmission center joint location. [0049] Transmission ratio in the swing direction was designed to TRatio,S = 10. The leg length was reduced to 4.5mm from the transmission center joint location to enable robot navigation through lateral constrained spaces with minimal interference to the side.
[0051] Thus, a swing input connection distance of si = 450^m was used in the transmission to the SFB. [0052] FIGs.8A and 8B illustrate characterization of leg mechanism 107 of FIG.4, in embodiments. FIG.8A is a graph 800 illustrating leg tip deflections in millimeters for a signal voltage V input to actuators 108 of FIG.1, where a lift line 802 indicates the lift deflection and a swing line 804 indicates the swing deflection, in embodiments. FIG.8B is a graph 850 illustrating blocked force at a tip of leg 106 for signal voltage V, where a lift line 852 indicates a lift force and a swing line 854 indicates a swing force, in embodiments. [0053] As shown in FIG.8A, the free tip position range of leg 106 was tested at various signal voltages. As desired, the swing deflection was consistently more than the lift deflection, with 2.85mm leg tip swing when powered at low frequency in the quasistatic region at 225V. The lift achieved 2.3mm at 225V without load, providing enough range to have leg lift under body load and external payload. [0054] As shown in FIG.8B, the leg tip blocked force was measured with a FUTEK load cell, with the lift direction achieving higher force than the swing direction. At 225V the lift block force is 14.3mN, indicating that a single leg may carry the full weight of body 102. Platform Overview [0055] FIGs.9A, 9B, and 9C are schematic plan views illustrating example body morphing of robot 100 of FIG.1, in embodiments. FIG.9A shows morphing of robot 100 with a width constraint, FIG.9B shows robot 100 when unconstrained, and FIG.9C shows morphing of robot 100 with a length constraint. When unconstrained, as shown in FIG.9B, flexure strength of flexures 114 causes robot 100 to assume a symmetric square body shape with a body length and body width of 20 mm for example. The combination of flexures 114 of body 102 allows robot 100 to compress down to 66% of its width or length and to expand up to 150% of its width or length. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0056] Robot 100 has a mass of 0.976 g, of which body 102, a carbon fiber body frame, weights 0.188 g, the eight piezoelectric actuators 108 weigh 0.544 g, and frames of actuators 108 weigh 0.180 g. Glue, solder and other small weights added up to an additional 0.064 g. In certain embodiments, body 102 is built using a multi-laminate manufacturing approach of two outer rigid structural layers of Carbon fiber (100^m thickness and a 0-90-0 fiber orientation), a center Kapton Polyimide film (25^m) layer for flexures, and two adhesive DuPont Pyralux FR1500 (13^m per layer). Flex sections 105 interconnecting adjacent leg modules 104 include flexure 114 to allow planar motion between two flat rigid panels 109 that rigidly couple with the adjacent leg modules. This enables body 102 to morph is response to external forces from an environment of robot 100 and allow robot 100 to passively interact with the environment. [0057] In certain embodiments, robot 100 is tethered for power and control. For ease of connection and testing pin headers were soldered to the top of each leg module 104 (see FIGs.11-14). The addition of solder, pin headers, connectors, and wires add a total of 380mg of payload to robot 100 during the described experiments. [0058] FIG.10 is a schematic illustrating example conformance of robot 100 of FIG. 1 moving through an environment 1000 with a lateral constraint 1002, in embodiments. Lateral constraint 1002 simulates a lateral narrowing of a passageway of an environment of robot 100 for example. At a first position, robot 100 is unconstrained and flexure strength of flexures 114 cause body 102 to assume a neutral (e.g., square) shape. Robot 100 is controlled to move from left to right through lateral constraint 1002 as indicated by arrows 1004 and 1006. As robot 100 enters lateral constraint 1002, body 102 receives external forces 1008 from lateral constraint and morphs, allowing robot 100 (shown as robot 100’) to continue motion through lateral constraint 1002. Particularly, external forces 1008 result from forward motion of robot 100 caused by leg modules 104. As shown for robot 100’, opposing flexures 114’ nearest walls of lateral constraint 1002 flex inwards and other opposing flexures flex outward allowing body 102 to laterally compress. As robot 100 exits lateral constraint 1002, external forces 1008 are removed and flexures 114 return body 102 to an uncompressed state, shown as robot 100’’. Demonstrated Performance [0059] FIG.11 is a composite image 1100 of five plan view images captured during a compliance demonstration where robot 100 of FIG.1 moves through a lateral constraint 1102. In this example, robot 100 moves from right to left through lateral constraint 1102. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT Robot 100 starts (at the right side) in a free neutral shape (e.g., square with a height of 20mm) and is trotting towards lateral constraint 1102, which has a width of 16.5mm. As robot 100 approaches the narrowest portion, external forces imparted on robot 100 by the environment morph body 102 into a narrower shape, allowing robot 100 to continue through lateral constraint 1102. Once robot 100 has pushed through the narrowest portion of lateral constraint 1102, external forces are removed and body 102 is allowed to return to its natural square shape (e.g., constraint free shape). [0060] FIG.12 is a composite image 1200 of four plan view images captured during a demonstration of robot 100 of FIG.1 moving in three directions without turning, in embodiments. Movement of robot 100 is controlled through an applied gait of each leg 106 and further, the movement control of each leg 106 with respect to the other legs. For example, gait algorithm 216 controls the gait and phase of each leg 106 movement to cause robot 100 to move in a desired direction. The robot is capable of various gaits including trot, walk, jump, and others. Popular gaits for robot control are a trot gait and a walk gait. The trot gait results in movement at a greater speed than the walk gait, whereas the walk gait provides greater stability of the robot as compared to the trot gait. The trot gait is characterized by the front-right and rear-left legs moving in sync and with a 180-degree phase offset to the front-left and rear-right legs, which are also moving in sync. These gaits result in straight line locomotion. Direction control is achieved by varying relative leg phase offsets. For example, gait algorithm 216 changes a phase of control signals to actuators 108 of each leg module 104 relative to signals to actuators 108 of other leg modules 104 to cause robot 100 to move in a specific direction. In the example of FIG.12, controller 202 invokes gait algorithm 216 to first control robot 100 to move in a right-to-left direction, as indicated by arrow 1202, then controls robot 100 to move in a top-to-bottom direction as indicated by arrow 1204 without turning, and then controls robot 100 to move in a left-to-right direction as indicated by arrow 1206. [0061] FIG.13 is a composite image 1300 of five plan view images captured during a demonstration of robot 100 of FIG.1 combining body morphing, as illustrated in FIG.11, with omnidirectional movement, as illustrated in FIG.12, to maneuver itself through a 90° confinement corner 1302, in embodiments. In this example, 90° confinement corner 1302 has insufficient space for robot 100 to rotate. Accordingly, in a compressed state, robot 100 changes its direction of motion at the corner to continue sideways, where body 102 morphs from a long-narrow shape to a short-wide shape as robot 100 transitions confinement corner 1302. As shown in FIG.13, robot 100 starts in a neutral body shape (e.g., non-constricted LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT square shape) on the right and trots to the left, as indicated by arrow 1304. As robot 100 enters a first confinement (e.g., 16.5mm), flexures 114 allow body 102 to morph into a long- narrow shape (e.g., a widthwise constriction or width compression) and continue through the constraint towards the corner. In this constrained environment, robot 100 does not have sufficient space to turn. Accordingly, at the corner, gait algorithm 216 causes robot 100 to adopt a sideways movement (top-to-bottom) as indicated by arrow 1306, and flexures 114 allow body 102 to morph from the long-narrow shape to a short-wide shape (e.g., a lengthwise constriction or length compression), allowing robot 100 to proceed in the direction indicated by arrow 1306. As robot 100 exits the confinement, flexures 114 cause body 102 to return to its natural shape (e.g., a non-constricted square shape). Advantageously, with both flexibility in shape and flexibility in movement direction, robot 100 demonstrates its ability to navigate constricted passages that change direction. Performance Enhancements [0062] FIG.14 is a perspective view of a robot 1400 that is a forerunner of robot 100 of FIG.1. Robot 100 includes several performance improvements over robot 1400, including reduced size that allows robot 100 to enter smaller spaces, flexibility tuning that improved compliance of body 102 to its environment, and improved maneuverability of robot 100 through improved gait control. [0063] Robot 1400 was unable to move effectively without careful body-compliance tuning. This is not surprising because the role of body mechanics during legged locomotion as a morphological computation principle is an area of active interest to biologists, physicists, and roboticists alike and remains a challenging problem yet to be fully understood. For example, the first couple of generations of the MIT Cheetah featured a compliant backbone which was later abandoned in part due to the challenges associated with tuning for effective locomotion. Robot 1400 also had significant slip during locomotion, highlighting the need for effective ground interactions for successful thrust generation. [0064] It was also observed that robot 1400 was unable to effectively utilize its entire bandwidth of leg cycling frequencies (up to the transmission resonances around 40 Hz) due to unfavorable body dynamics. The leg modules of robot 1400 were not identical in their performance despite best efforts to match them, and more importantly, the articulated joints degraded during the process of robot testing. [0065] The reduction in size from robot 1400 to robot 100 required significant redesign of linkage portions due to manufacturing size limit constraints. Components were in LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT general scaled down to 60% of their original dimensions, reducing the overall body dimensions to this percentage. Further, components were modified to overcome the limitation of robot 1400. First, robot 100 locomotes without ’fixing’ the body shape in open environments as required by robot 1400 and unlocks a new capability of laterally confined locomotion by passively adapting to its external constraints as illustrated by FIGs.10, 11 and 13. Second, robot 100 is omnidirectional and may move forward and sideways with equal ease, which drastically increases its planar maneuverability. [0066] The transmission flexure joints in robot 100 were increased in stiffness, as compared to robot 1400, (e.g., ^4.6× increased stiffness, where the flexure layer thickness is increased from 7.5^m to 12.5^m) to improve the lifetime of the mechanics. Based on initial experiments, robot 100 is expected to maintain performance to at least 100,000 cycles, and may be further tweaked for desired application specifications. [0067] Actuators 108 in robot 100 are reduced to ^80% of those in robot 1400 to maximize the power and locomotion performance of robot 100. This effectively reduced their weight by ^50%, while retaining 65% of the displacement and producing similar force as actuators of robot 1400. The payload body ratio (rpl) of robot 100 is defined as the minimum total load the robot can hold and still have the ability to take individual leg steps before collapsing under load. At the limit 3 legs need to be able to support the load, with the fourth leg taking a step.
[
0068] This changes the force to robot mass ratio significantly from ଷൈଽ.ହ
ൌ ଶ.ହ^ൈଽ.଼^ ൌ 1.13 to ^^^ ൌ ଷൈ^ସ.ଷ ^.ଽ^ൈଽ.଼^ ൌ 4.51. Robot 100 walks under its own mass with an additional payload with the actuators providing enough force to support 4.51 times the current load the robot mass is requiring from the actuators. [0069] The internal leg transmission pieces in robot 100 are generally scaled down to 60% of their dimension in robot 1400, up to a minimum flexure width of 1mm for manufacturing reliability. This scaling also forces the redesign of certain transmission parts to permit origami folding during assembly. To account for increased relative actuator force, the mechanical ground of the leg modules in robot 100 is reinforced with a double layer fold at the location of lift and swing input to SFB linkage 110. Additionally, the actuator frame is extended to support the transmission point as a perpendicular rib, providing significant additional strength to the leg module. The miniaturization also forced the linkage inputs to LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT the SFB to be located on the same plane as the main joints from of swing and lift which connect the transmission to the body ground frame. Therefore, during the origami folding, the input joints segments are double layer folded to connect partially through the front layer, ensuring the planar joint alignment, minimizing the effects of directional biasing between lift and swing. [0070] The transmission ratios and flexure dimensions are optimized to improve performance of robot 100 over robot 1400. Body joint stiffness of robot 1400 was not tuned and therefore robot 1400 was unable to move well when unconfined (e.g., ten times slower than when confined). Robot 100 is over three times faster than robot 1400 when unconfined. [0071] FIGs 3B and 3D, as described above, illustrate stiffened ground 302, stiffened swing input 304, and stiffened lift input 306 of leg module 104. With the addition of the double layer fold at the location of lift and swing inputs to SFB linkage 110, leg modules 104 of robot 100 are reinforced and transmission is capable of handling high off-axis forces. Areas of stiffened ground 302, stiffened swing input 304, and stiffened lift input 306 for robot 100 are larger than those of robot 1400, resulting in improved stiffness at the inputs to SFB linkage 110 as compared to robot 1400. In certain embodiments, gait algorithm 216 of FIG.2A, may modify gait of legs 106 based on morphing of body 102. For example, gait algorithm 216 may modify the gait to compensate for orientation changes of leg module 104 relative to a desired locomotion direction of robot 100 resulting from morphing of body 102. [0072] Gait algorithm 216 is improved (as compared to gait algorithm of robot 1400) to control leg modules 104 of robot 100 to switch from moving in a confined space forward- backward to left-right with equal speed, as shown in FIG.13. For example, gait algorithm 216 modifies coordination of leg modules 104 to change the direction of movement and the shape of body 102. Gait algorithm 216 thereby provides omnidirectional maneuvering of robot 100 that has not been previously demonstrated for any legged robotic platform during confined locomotion. Additional Embodiments [0073] FIG.15 is a schematic illustrating one example robot 1500 with six leg modules 1504 and six flex sections 1505 that are interconnected to form a body 1502 that is a closed kinematic chain. Leg modules 1504 and flex sections 1505 are similar to leg module 104 and flex sections 105 of robot 100 of FIG.1. Advantageously, body 1502 may morph and pass through a lateral constraint that is smaller than a width of robot 1500. With four legs, robot 100 is the simplest instantiation of shape morphing in legged insect scale robots. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT Robot 1500, with two additional leg modules 1504, provides specific advantages. For example, with six legs, robot 1500 may always have three legs on the ground during a trotting gait for static stability and thereby reduce the likelihood of robot 1500 falling down. [0074] FIG.16 is a schematic illustrating one example robot 1600 with eight leg modules 1604 and eight flex sections 1605 that are interconnected to form a body 1602 that is a closed kinematic chain. Leg modules 1604 and flex sections 1605 are similar to leg module 104 and flex sections 105 of robot 100 of FIG.1. Advantageously, body 1602 may morph and pass through a lateral constraint that is smaller than a width of robot 1600. With eight legs, robot 1600 may use the two forward facing legs as feelers or as manipulators, as done by insects and spiders. In embodiments with more legs (e.g., ten or more), the robot is expected to maintain locomotion performance even when one or more leg modules fail, similar to centipedes or millipedes. [0075] Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween. Combination Of Features [0076] (A1) A modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance; wherein the flexure has a flexural strength selected to allow the body to morph in response to a force resulting from self-propelled motion of the robot into a constricted environment. [0077] (A2) In embodiments of (A1), the flexural strength causing the body to return to an natural state when the force is removed. [0078] (A3) In embodiments of either (A1) or (A2), the body forming a closed kinematic chain. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0079] (A4) In any of the embodiments of (A1)–(A3), the at least four flex sections being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0080] (A5) In any of the embodiments of (A1)–(A4), the flexure being formed with a thickness of 12.5^m from the center flexible layer including a Kapton Polyimide film. [0081] (A6) In any of the embodiments of (A1)–(A5), each of the at least two outer rigid structural layers being carbon fiber with a100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0082] (A7) In any of the embodiments of (A1)–(A6), each leg module further including a lift actuator that moves the leg in a lift direction and a swing actuator that move the leg in a swing direction. [0083] (A8) Any of the embodiments of (A1)–(A7) further including a controller implementing a gait algorithm to control the lift actuator and the swing actuator of each leg module to cause the leg to move with a gait. [0084] (A9) In any of the embodiments of (A1)–(A8), the gait algorithm controlling the gait of each leg module to cause the robot to move in a desired direction. [0085] (A10) In any of the embodiments of (A1)-(A9), the gait algorithm controlling the gait of each leg module to cause the robot to change a direction of movement during confined locomotion. [0086] (A11) In any of the embodiments of (A1)-(A10), the change in direction causing the single body to change shape. [0087] (A12) In any of the embodiments of (A1)–(A11), each of the four leg modules including a spherical five-bar (SFB) linkage driven by the lift actuator and the swing actuator. [0088] (A13) In any of the embodiments of (A1)–(A12), a mechanical ground of each of the four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0089] (A14) In any of the embodiments of (A1)–(A13), the body further including additional leg modules and flex sections. [0090] (A15) In any of the embodiments of (A1)–(A14),, each leg module having two actuators that mechanically couple with, and drive, the leg. [0091] (A16) In any of the embodiments of (A1)–(A15), the actuators including piezoelectric actuators. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0092] (A17) In any of the embodiments of (A1)–(A16), the body including rigid, flexible and adhesive layers. [0093] (A18) In any of the embodiments of (A1)–(A17), the body forming a symmetrical shape when the body is unconstrained. [0094] (A19) In any of the embodiments of (A1)–(A18), the body having a body length and a body width that are equal when the body is unconstrained. [0095] (A20) In any of the embodiments of (A1)–(A19), the body being capable of: (a) compressing to two-thirds of the body length through an external force of a constraint, or (b) compressing to two-thirds of the body width through the external force. [0096] (B1) A modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance. [0097] (B2) In embodiments of (B1), the flexure has a flexural strength selected to allow the body to morph in response to a force resulting from self-propelled motion of the robot into a constricted environment. [0098] (B3) In embodiments of either (B1) or (B2), the flexural strength causing the body to return to an natural state when the force is removed. [0099] (B4) In any of the embodiments of (B1)–(B3), the body forming a closed kinematic chain. [0100] (B5) In any of the embodiments of (B1)–(B4), the four flex sections being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0101] (B6) In any of the embodiments of (B1)–(B5), the flexure being formed with a thickness of 12.5^m from the center flexible layer including a Kapton Polyimide film. [0102] (B7) In any of the embodiments of (B1)–(B6), each of the at least two outer rigid structural layers being Carbon fiber with a 100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0103] (B8) In any of the embodiments of (B1)–(B7), each leg module having a lift actuator and a swing actuator that mechanically couple with, and drive, the leg. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0104] (B9) In any of the embodiments of (B1)–(B8), the lift actuator and the swing actuator each including a piezoelectric actuator. [0105] (B10) In any of the embodiments of (B1)–(B9), each of the at least four leg modules including a spherical five-bar (SFB) linkage that interlinks the two and couples to a leg output. [0106] (B11) In any of the embodiments of (B1)–(B10), a mechanical ground of each of the at least four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0107] (B12) Any of the embodiments of (B1)–(B11), further including a controller implementing a gait algorithm to control the lift actuator and the swing actuator of each leg module to cause the leg to move with a gait. [0108] (B13) In any of the embodiments of (B1)–(B12), the gait algorithm controlling the gait of each leg module to cause the robot to move in a desired direction. [0109] (B14) In any of the embodiments of (B1)–(B13), the gait algorithm controlling the gait of each leg module to cause the robot to change a direction of movement during confined locomotion. [0110] (B15) In any of the embodiments of (B1)–(B14), the change in direction causing the single body to change shape. [0111] (B16) In any of the embodiments of (B1)–(B15), the body including rigid, flexible and adhesive layers. [0112] (B17) In any of the embodiments of (B1)–(B16), the body forming a symmetrical shape when the body is unconstrained. [0113] (B18) In any of the embodiments of (B1)–(B17), the body having a body length and a body width that are equal when the body is unconstrained. [0114] (B19) In any of the embodiments of (B1)–(B18), the body being capable of: (a) compressing to two-thirds of the body length through an external force of a constraint, or (b) compressing to two-thirds of the body width through the external force. [0115] (B20) In any of the embodiments of (B1)–(B19), each of the at least four leg modules forming a flat rigid section of the body. [0116] (B22) In any of the embodiments of (B1)–(B21), the lateral body compliance is distributed through flexure geometry to enable the robot to maneuver through confined terrain narrower than a neutral size of the body. [0117] (C1) A leg module for a modular origami shape-morphing soft exoskeletal legged robot, including: a spherical five-bar (SFB) linkage that interlinks the two and couples 19 LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT to a leg output with at least two degrees-of-freedom; two actuators that mechanically couple with a lift input and a swing input of the SFB linkage; and a mechanical ground formed between the actuators and the SFB linkage. [0118] (C2) In the embodiment (C1), the SFB linkage, and the leg being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0119] (C3) In either of the embodiments (C1) or (B2), each of the at least two outer rigid structural layers being Carbon fiber with a 100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0120] (C4) In any of the embodiments of (C1)–(C3), a mechanical ground of each of the at least four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0121] (C5) In any of the embodiments of (C1)–(C4), the actuators including piezoelectric actuators. LEGAL\71977578\6
[0048] The leg tip is calculated to be placed 6.25mm below the transmission center joint location. [0049] Transmission ratio in the swing direction was designed to TRatio,S = 10. The leg length was reduced to 4.5mm from the transmission center joint location to enable robot navigation through lateral constrained spaces with minimal interference to the side.
ൌ ଶ.ହ^ൈଽ.଼^ ൌ 1.13 to ^^^ ൌ ଷൈ^ସ.ଷ ^.ଽ^ൈଽ.଼^ ൌ 4.51. Robot 100 walks under its own mass with an additional payload with the actuators providing enough force to support 4.51 times the current load the robot mass is requiring from the actuators. [0069] The internal leg transmission pieces in robot 100 are generally scaled down to 60% of their dimension in robot 1400, up to a minimum flexure width of 1mm for manufacturing reliability. This scaling also forces the redesign of certain transmission parts to permit origami folding during assembly. To account for increased relative actuator force, the mechanical ground of the leg modules in robot 100 is reinforced with a double layer fold at the location of lift and swing input to SFB linkage 110. Additionally, the actuator frame is extended to support the transmission point as a perpendicular rib, providing significant additional strength to the leg module. The miniaturization also forced the linkage inputs to LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT the SFB to be located on the same plane as the main joints from of swing and lift which connect the transmission to the body ground frame. Therefore, during the origami folding, the input joints segments are double layer folded to connect partially through the front layer, ensuring the planar joint alignment, minimizing the effects of directional biasing between lift and swing. [0070] The transmission ratios and flexure dimensions are optimized to improve performance of robot 100 over robot 1400. Body joint stiffness of robot 1400 was not tuned and therefore robot 1400 was unable to move well when unconfined (e.g., ten times slower than when confined). Robot 100 is over three times faster than robot 1400 when unconfined. [0071] FIGs 3B and 3D, as described above, illustrate stiffened ground 302, stiffened swing input 304, and stiffened lift input 306 of leg module 104. With the addition of the double layer fold at the location of lift and swing inputs to SFB linkage 110, leg modules 104 of robot 100 are reinforced and transmission is capable of handling high off-axis forces. Areas of stiffened ground 302, stiffened swing input 304, and stiffened lift input 306 for robot 100 are larger than those of robot 1400, resulting in improved stiffness at the inputs to SFB linkage 110 as compared to robot 1400. In certain embodiments, gait algorithm 216 of FIG.2A, may modify gait of legs 106 based on morphing of body 102. For example, gait algorithm 216 may modify the gait to compensate for orientation changes of leg module 104 relative to a desired locomotion direction of robot 100 resulting from morphing of body 102. [0072] Gait algorithm 216 is improved (as compared to gait algorithm of robot 1400) to control leg modules 104 of robot 100 to switch from moving in a confined space forward- backward to left-right with equal speed, as shown in FIG.13. For example, gait algorithm 216 modifies coordination of leg modules 104 to change the direction of movement and the shape of body 102. Gait algorithm 216 thereby provides omnidirectional maneuvering of robot 100 that has not been previously demonstrated for any legged robotic platform during confined locomotion. Additional Embodiments [0073] FIG.15 is a schematic illustrating one example robot 1500 with six leg modules 1504 and six flex sections 1505 that are interconnected to form a body 1502 that is a closed kinematic chain. Leg modules 1504 and flex sections 1505 are similar to leg module 104 and flex sections 105 of robot 100 of FIG.1. Advantageously, body 1502 may morph and pass through a lateral constraint that is smaller than a width of robot 1500. With four legs, robot 100 is the simplest instantiation of shape morphing in legged insect scale robots. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT Robot 1500, with two additional leg modules 1504, provides specific advantages. For example, with six legs, robot 1500 may always have three legs on the ground during a trotting gait for static stability and thereby reduce the likelihood of robot 1500 falling down. [0074] FIG.16 is a schematic illustrating one example robot 1600 with eight leg modules 1604 and eight flex sections 1605 that are interconnected to form a body 1602 that is a closed kinematic chain. Leg modules 1604 and flex sections 1605 are similar to leg module 104 and flex sections 105 of robot 100 of FIG.1. Advantageously, body 1602 may morph and pass through a lateral constraint that is smaller than a width of robot 1600. With eight legs, robot 1600 may use the two forward facing legs as feelers or as manipulators, as done by insects and spiders. In embodiments with more legs (e.g., ten or more), the robot is expected to maintain locomotion performance even when one or more leg modules fail, similar to centipedes or millipedes. [0075] Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween. Combination Of Features [0076] (A1) A modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance; wherein the flexure has a flexural strength selected to allow the body to morph in response to a force resulting from self-propelled motion of the robot into a constricted environment. [0077] (A2) In embodiments of (A1), the flexural strength causing the body to return to an natural state when the force is removed. [0078] (A3) In embodiments of either (A1) or (A2), the body forming a closed kinematic chain. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0079] (A4) In any of the embodiments of (A1)–(A3), the at least four flex sections being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0080] (A5) In any of the embodiments of (A1)–(A4), the flexure being formed with a thickness of 12.5^m from the center flexible layer including a Kapton Polyimide film. [0081] (A6) In any of the embodiments of (A1)–(A5), each of the at least two outer rigid structural layers being carbon fiber with a100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0082] (A7) In any of the embodiments of (A1)–(A6), each leg module further including a lift actuator that moves the leg in a lift direction and a swing actuator that move the leg in a swing direction. [0083] (A8) Any of the embodiments of (A1)–(A7) further including a controller implementing a gait algorithm to control the lift actuator and the swing actuator of each leg module to cause the leg to move with a gait. [0084] (A9) In any of the embodiments of (A1)–(A8), the gait algorithm controlling the gait of each leg module to cause the robot to move in a desired direction. [0085] (A10) In any of the embodiments of (A1)-(A9), the gait algorithm controlling the gait of each leg module to cause the robot to change a direction of movement during confined locomotion. [0086] (A11) In any of the embodiments of (A1)-(A10), the change in direction causing the single body to change shape. [0087] (A12) In any of the embodiments of (A1)–(A11), each of the four leg modules including a spherical five-bar (SFB) linkage driven by the lift actuator and the swing actuator. [0088] (A13) In any of the embodiments of (A1)–(A12), a mechanical ground of each of the four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0089] (A14) In any of the embodiments of (A1)–(A13), the body further including additional leg modules and flex sections. [0090] (A15) In any of the embodiments of (A1)–(A14),, each leg module having two actuators that mechanically couple with, and drive, the leg. [0091] (A16) In any of the embodiments of (A1)–(A15), the actuators including piezoelectric actuators. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0092] (A17) In any of the embodiments of (A1)–(A16), the body including rigid, flexible and adhesive layers. [0093] (A18) In any of the embodiments of (A1)–(A17), the body forming a symmetrical shape when the body is unconstrained. [0094] (A19) In any of the embodiments of (A1)–(A18), the body having a body length and a body width that are equal when the body is unconstrained. [0095] (A20) In any of the embodiments of (A1)–(A19), the body being capable of: (a) compressing to two-thirds of the body length through an external force of a constraint, or (b) compressing to two-thirds of the body width through the external force. [0096] (B1) A modular origami shape-morphing soft exoskeletal legged robot, including: at least four leg modules, each having a leg with at least two degrees-of-freedom; and at least four flex sections, each having two rigid panels coupled together by a flexure with a single degree-of-freedom; wherein each flex section is positioned between two adjacent leg modules and each of the rigid panels fixedly couples with a different one of the leg modules to form a single body with articulated morphology for lateral compliance. [0097] (B2) In embodiments of (B1), the flexure has a flexural strength selected to allow the body to morph in response to a force resulting from self-propelled motion of the robot into a constricted environment. [0098] (B3) In embodiments of either (B1) or (B2), the flexural strength causing the body to return to an natural state when the force is removed. [0099] (B4) In any of the embodiments of (B1)–(B3), the body forming a closed kinematic chain. [0100] (B5) In any of the embodiments of (B1)–(B4), the four flex sections being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0101] (B6) In any of the embodiments of (B1)–(B5), the flexure being formed with a thickness of 12.5^m from the center flexible layer including a Kapton Polyimide film. [0102] (B7) In any of the embodiments of (B1)–(B6), each of the at least two outer rigid structural layers being Carbon fiber with a 100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0103] (B8) In any of the embodiments of (B1)–(B7), each leg module having a lift actuator and a swing actuator that mechanically couple with, and drive, the leg. LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT [0104] (B9) In any of the embodiments of (B1)–(B8), the lift actuator and the swing actuator each including a piezoelectric actuator. [0105] (B10) In any of the embodiments of (B1)–(B9), each of the at least four leg modules including a spherical five-bar (SFB) linkage that interlinks the two and couples to a leg output. [0106] (B11) In any of the embodiments of (B1)–(B10), a mechanical ground of each of the at least four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0107] (B12) Any of the embodiments of (B1)–(B11), further including a controller implementing a gait algorithm to control the lift actuator and the swing actuator of each leg module to cause the leg to move with a gait. [0108] (B13) In any of the embodiments of (B1)–(B12), the gait algorithm controlling the gait of each leg module to cause the robot to move in a desired direction. [0109] (B14) In any of the embodiments of (B1)–(B13), the gait algorithm controlling the gait of each leg module to cause the robot to change a direction of movement during confined locomotion. [0110] (B15) In any of the embodiments of (B1)–(B14), the change in direction causing the single body to change shape. [0111] (B16) In any of the embodiments of (B1)–(B15), the body including rigid, flexible and adhesive layers. [0112] (B17) In any of the embodiments of (B1)–(B16), the body forming a symmetrical shape when the body is unconstrained. [0113] (B18) In any of the embodiments of (B1)–(B17), the body having a body length and a body width that are equal when the body is unconstrained. [0114] (B19) In any of the embodiments of (B1)–(B18), the body being capable of: (a) compressing to two-thirds of the body length through an external force of a constraint, or (b) compressing to two-thirds of the body width through the external force. [0115] (B20) In any of the embodiments of (B1)–(B19), each of the at least four leg modules forming a flat rigid section of the body. [0116] (B22) In any of the embodiments of (B1)–(B21), the lateral body compliance is distributed through flexure geometry to enable the robot to maneuver through confined terrain narrower than a neutral size of the body. [0117] (C1) A leg module for a modular origami shape-morphing soft exoskeletal legged robot, including: a spherical five-bar (SFB) linkage that interlinks the two and couples 19 LEGAL\71977578\6
Attorney Docket No: UOCO.P2087WO/00618198 CU6349B-PCT to a leg output with at least two degrees-of-freedom; two actuators that mechanically couple with a lift input and a swing input of the SFB linkage; and a mechanical ground formed between the actuators and the SFB linkage. [0118] (C2) In the embodiment (C1), the SFB linkage, and the leg being formed of a laminate including at least two outer rigid structural layers, a center flexible layer, and two adhesive layers. [0119] (C3) In either of the embodiments (C1) or (B2), each of the at least two outer rigid structural layers being Carbon fiber with a 100^m thickness and a 0-90-0 fiber orientation, the center flexible layer being a kapton polyimide film of 25^m, and the two adhesive layers being 13^m per layer. [0120] (C4) In any of the embodiments of (C1)–(C3), a mechanical ground of each of the at least four leg modules having a double layer fold at locations of lift input and swing input to the SFB linkage. [0121] (C5) In any of the embodiments of (C1)–(C4), the actuators including piezoelectric actuators. LEGAL\71977578\6