2,697 research outputs found
Motion Planning of Legged Robots
We study the problem of computing the free space F of a simple legged robot
called the spider robot. The body of this robot is a single point and the legs
are attached to the body. The robot is subject to two constraints: each leg has
a maximal extension R (accessibility constraint) and the body of the robot must
lie above the convex hull of its feet (stability constraint). Moreover, the
robot can only put its feet on some regions, called the foothold regions. The
free space F is the set of positions of the body of the robot such that there
exists a set of accessible footholds for which the robot is stable. We present
an efficient algorithm that computes F in O(n2 log n) time using O(n2 alpha(n))
space for n discrete point footholds where alpha(n) is an extremely slowly
growing function (alpha(n) <= 3 for any practical value of n). We also present
an algorithm for computing F when the foothold regions are pairwise disjoint
polygons with n edges in total. This algorithm computes F in O(n2 alpha8(n) log
n) time using O(n2 alpha8(n)) space (alpha8(n) is also an extremely slowly
growing function). These results are close to optimal since Omega(n2) is a
lower bound for the size of F.Comment: 29 pages, 22 figures, prelininar results presented at WAFR94 and IEEE
Robotics & Automation 9
AAO Starbugs: software control and associated algorithms
The Australian Astronomical Observatory's TAIPAN instrument deploys 150
Starbug robots to position optical fibres to accuracies of 0.3 arcsec, on a 32
cm glass field plate on the focal plane of the 1.2 m UK-Schmidt telescope. This
paper describes the software system developed to control and monitor the
Starbugs, with particular emphasis on the automated path-finding algorithms,
and the metrology software which keeps track of the position and motion of
individual Starbugs as they independently move in a crowded field. The software
employs a tiered approach to find a collision-free path for every Starbug, from
its current position to its target location. This consists of three
path-finding stages of increasing complexity and computational cost. For each
Starbug a path is attempted using a simple method. If unsuccessful,
subsequently more complex (and expensive) methods are tried until a valid path
is found or the target is flagged as unreachable.Comment: 10 pages, to be published in Proc. SPIE 9913, Software and
Cyberinfrastructure for Astronomy IV; 201
Biomechanical study of the Spider Crab as inspiration for the development of a biomimetic robot
A problem faced by oil companies is the maintenance of the location register of pipelines that cross the surf zone, the regular survey of their location, and also their inspection. A survey of the state of art did not allow identifying operating systems capable of executing such tasks. Commercial technologies available on the market also do not address this problem and/or do not satisfy the presented requirements. A possible solution is to use robotic systems which have the ability to walk on the shore and in the surf zone,
subject to existing currents and ripples, and being able to withstand these ambient conditions. In this sense,
the authors propose the development of a spider crab biologically inspired robot to achieve those tasks. Based on these ideas, this work presents a biomechanical study of the spider crab, its modeling and simulation using the SimMechanics toolbox of Matlab/Simulink, which is the first phase of this more vast project. Results show a robot model that is moving in an “animal like” manner, the locomotion, the algorithm presented in this paper allows the crab to walk sideways, in the desired direction.N/
Comparison of Spider-Robot Information Models
The paper deduces a mathematical model of a spider-robot with six three-link limbs. Many limbs with a multi-link structure greatly complicate the process of synthesizing a model, since in total the robot has twenty-four degrees of freedom, i.e., three coordinates of the center of mass of the body in space, three angles of rotation of the body relative to its center of mass and three degrees of freedom for each limb, to describe the position of the links. The derived mathematical model is based on the Lagrange equations with a further transformation of the equations to the Cauchy normal form in a matrix form. To test the resulting model in a SimInTech environment, an information model is synthesized and two simple experiments ar carried out to simulate the behavior of real spiders: moving forward in a straight line and turning in place at a given angle. The experimental results demonstrate that the synthesized information model can well cope with the tasks and the mathematical model underlying it can be used for further research
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