Design of the I-BoomCopter UAV for Remote Sensor Mounting

This paper presents the design of the Interacting-BoomCopter (I-BoomCopter) unmanned aerial vehicle (UAV) for mounting a remote sensor package on a vertical surface. Critical to the design is the novel, custom, light-weight passive end-effector. The end-effector has a forward-facing sonar sensor and in-line force sensor to enable autonomous sensor mounting tasks. The I-BoomCopter’s front boom is equipped with a horizontally-mounted propeller which can provide forward and reverse thrust with zero roll and pitch angles. The design and modeling of the updated I-BoomCopter platform is presented along with prototype flight test results. A teleoperated wireless camera sensor mounting task examines the updated platform’s suitability for mounting remote sensor packages.

Design and Analysis of Reduced Degree of Freedom Modular Snake Robot

This paper presents the design and analysis of an underactuated, cable driven mechanism for use in a modular robotic snake. The proposed mechanism is composed of a chain of rigid links that rotate on parallel revolute joints and are actuated by antagonistic cable pairs and a multi-radius pulley. This design aims to minimize the cross sectional area of cable actuated robotic snakes and eliminate undesirable nonlinearities in cable displacements. A distinctive feature of this underactuated mechanism is that it allows planar serpentine locomotion to be accomplished with only two modular units, improving the snake’s ability to conform to desired curvature profiles and minimizing the control complexity involved in snake locomotion. First, the detailed mechanism and cable routing scheme are presented, after which the kinematics and dynamics of the system are derived and a comparative analysis of cable routing schemes is performed, to assist with design synthesis and control. The moment of inertia of the mechanism is modeled, for future use in the implementation of three-dimensional modes of snake motion. Finally, a planar locomotion strategy for snake robots is devised, demonstrated in simulation, and compared with previous studies.

Finite Position Synthesis of 5-SS Platform Linkages Including Partially Specified Joint Locations

A 5-SS platform linkage generates a one-degree-of-freedom motion of a moving platform such that each of five moving points on the platform is constrained on a sphere, or in its degenerated case, on a plane. It has been well established a 5-SS platform linkage can be made to guide though seven positions exactly. This paper investigates the cases when the number of given positions are less than seven that allows for partial specification of locations of the moving points. A recently developed novel algorithm with linear structure in the design equations has been extended for the solution of the problem. The formulation of this expanded motion generation problem unifies the treatment of the input positions and constraints on the moving and fixed joints associated with the 5-SS platform linkage. Numerical examples are provided to show the effectiveness of the unified algorithm.

Design and Comparative Analysis of Linear Guides for Refreshable Braille Displays

Linear guides are extensively employed in several industrial applications. Miniaturization, minimal friction, cost efficiency and low maintenance are the major challenges faced while developing a linear motion system. This paper presents design and realization of such systems, overcoming the aforementioned challenges. Linear guidance mechanisms, suitable for implementing latching in Refreshable Braille Displays are proposed, where uniform behavior under eccentric loading is required. Several low cost, reliable and efficient guide mechanisms with predetermined dimensional constraints have been designed. Seven mechanisms are illustrated and analyzed in this paper, which includes both, traditional contact-based mechanisms and compliant mechanisms that offer contact-less motion. The paper further compares the functionality, cost feasibility and ease of manufacturing and assembly of these mechanisms.

Designing for Power Transfer Across Fold-Lines in Mechanisms With Origami-Like Movement Using Surrogate Folds

As mechanisms with origami-like movement increase in popularity, there is a need for conducting electrical power across folds. This need could potentially be filled by the use of surrogate folds. Surrogate folds are a localized reduction in stiffness in a given direction allowing the material to function like a fold. Current methods for conducting across folds are reviewed along with current opportunities. A framework for designing conductive surrogate folds that can be adapted to fit specific applications is presented. Equations for calculating the resistance in single surrogate folds as well as arrays are given. Prototypes of several conductive joints are presented and discussed. The framework is then followed in the designing and manufacturing of a conductive origami-inspired mechanism.

On-Line Task Decomposition for Collaborative Surveillance of Marine Environment by a Team of Unmanned Surface Vehicles

In this paper, we introduce an approach for decomposing exploration tasks among multiple Unmanned Surface Vehicles (USVs) in port regions. In order to ensure effective distribution of the workload, the algorithm has to consider the effects of the environment on the physical constraints of the USVs. The performance of the USV is influenced by the surface currents, risk of collision with the civilian traffic, and varying depths as a result of tides, and weather. In our approach, we want the team of USVs to explore certain region of the harbor. The algorithm has to decompose the region of interest into multiple sub-regions by considering the maximum operating velocity of each USV in the given environmental conditions. The algorithm overlays a 2D grid upon a given map to convert it to an occupancy grid, and then proceeds to partition the region of interest among the multiple USVs assigned to explore the region. During partitioning, each USV covers the maximum area that is possible by operating at maximum velocity at each time-step. The objective is to minimize the time taken for the last USV to finish claiming its area exploration. We use the particle swarm optimization (PSO) method to compute the optimal region partitions. The method is verified by running simulations in different test environments. We also analyze the performance of the developed method in environments with unknown velocity profiles.

Exploration of Turning Strategies for an Unconventional Non-Anthropomorphic Bipedal Robot

This paper presents our findings in exploring various approaches for turning on a novel prototype biped which takes inspiration from humanoids, but features fundamental differences that increase its stability while reducing its cost and complexity. This non-anthropomorphic robotic system modifies the traditional humanoid form by aligning the legs in the sagittal plane and adding a compliant element to the feet. As this approach to locomotion is relatively new, turning methods have yet to be explored. Turning on this unique platform is a nontrivial problem that we examined by adding additional DoF in the forms of arms or hip actuators. The turning strategies tested include using the hand or foot as a pivot point, utilizing the arms like a tail or reaction wheel, and adding another DoF to each leg. The methods were tested quantitatively to assess their rotational accuracy and qualitatively to evaluate their viability in certain situations.

Conjugation Curvature Theory of Higher Pairs

The paper pioneers the higher order conjugation theory that elevates the current Camus and Litvin based conjugation theory to a new level by offering the methodology to enable explicitly selecting conjugate pairs to meet the prescribed intrinsic contact characteristics or performance for contact strength. A conjugation theorem is proposed, in which a three-body conjugation system is characterized by the coinciding instant centers and from which the theory is established. Instantaneous invariants are introduced to characterize the instantaneous motion of a three-body conjugation system. The loci of points that generate conjugate pairs with the common relative curvature as well as first and second order stationary relative curvature are presented. These curvature properties determine the contact pattern and therefore the contact strength. An immediate and important application is on gear tooth profile synthesis. The proposed theory offers the design freedom that breaks the traditional constraint of using a specific curve, such as involute. It therefore fills a void in gear tooth profile synthesis and brings light to the question on seeking the strongest tooth profiles. On the other hand, this is the first kinematic synthesis theory that generate both elements of a higher pair simultaneously for a prescribed contact performance. It is a contrast to the conventional Burmester theory by using RR, PR, or RP dyads to form a linkage.

Design Optimization of Folding Solar Powered Autonomous Underwater Vehicles Using Origami Architecture

Recently, the importance of design process with unknown parameter increased. On the other hand, the design of Autonomous Underwater Vehicles (AUVs) is a difficult challenge since it requires the consideration of various aspects such as mission range, controllability, energy source, and carrying capacity. A design process for novel type of AUV constructed using an origami-based structure that includes active material actuators and solar panels is proposed in this paper. To increase the efficiency in the three-dimensional shape modeling of the AUV, the shape of the outer surface is parameterized by a finite set of variables using shape functions. Here, the AUV should operate underwater via electrical power with the batteries being charged periodically using solar panels. The ability of the AUV to transport cargo such as instrumentation is also addressed. The design parameters include the total height and width of the AUV. As these dimensions of the AUV might vary in a non-preferential manner based on particular mission goals, these dimensions are considered as design parameters in a multi-objective optimization setting. The Predictive Parameterized Pareto Genetic Algorithm (P3GA) is selected as the optimization method to determine a Pareto frontier of design options with desired characteristics for a variety of missions for the AUV. The evaluation of each AUV design entails quantitative assessment of the origami fold pattern determined using a method developed by the authors and Computational Fluid Dynamics (CFD) analysis. The development of a design process that addresses the design optimization of the AUV considering its hydrodynamic performance and origami aspects is the main topic of this paper.

Self-Locking Origami Structures and Locking-Induced Piecewise Stiffness

The folding motion of an origami structure can be stopped at a non-flat position when two of its facets bind together. Such facet-binding will induce self-locking so that the overall origami structure can stay at a pre-specified configuration without the help of additional locking devices or actuators. This research investigates the designs of self-locking origami structures and the locking-induced kinematical and mechanical properties. We show that incorporating multiple cells of the same type but with different geometry could significantly enrich the self-locking origami pattern design. Meanwhile, it offers remarkable programmability to the kinematical properties of the self-locking origami structures, including the number and position of locking points, and the deformation range. Self-locking will also affect the mechanical characteristics of the origami structures. Experiments and finite element simulations reveal that the structural stiffness will experience a sudden jump with the occurrence of self-locking, inducing a piecewise stiffness profile. The results of this research would provide design guidelines for developing self-locking origami structures and metamaterials with excellent kinematical and stiffness characteristics, with many potential engineering applications.