# 0.7 Robotic path planning and protein modeling  (Page 2/3)

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In the above figures, the configuration space is two dimensional because the robot has two degrees of freedom. If the heading of the robot mattered (i.e., if the robot were not circular), then a configuration would consist of a position and an orientation. The configuration space would therefore be three dimensional. If the robot had a rotatable joint, this would add another degree of freedom and another dimension to the C-space.

## The path planning problem

The robotic path planning problem is, given a robot, a work space, and starting and goal configurations for the robot in the work space, find a collision-free path for the robot from the starting configuration to the goal, if one exists. Otherwise determine that no such path exists. An extensive introduction to the path planning problem and existing solutions may be found in .

Early approaches to path planning included:

• Construction of visibility graphs between the vertices of C-space obstacles.
• Decomposition of the C-space, effectively into subproblems.
• Potential field methods, in which the goal exerts an attractive force on the robot, and the obstacles exert repulsive forces.
The first two methods scale poorly with the dimensionality of the C-space, since the complexity of the C-space affects their run time. Potential fields are subject to local minima. A robot moving down the potential gradient might get stuck in a potential well before it reaches the global potential minimum at the goal.

## Sampling-based path planning

One solution to the scalability problem was to find methods whose run time does not depend on the dimensionality of the C-space, but on some other factor. This led to sampling-based path planning. Rather than making some explicit analysis of the whole C-space, sampling based planners built their representation of C-space by sampling random configurations and using a fast collision checker to determine whether they are in collision.

The basis of many modern sampling-based planners is the Probabilistic Roadmap Method (PRM) . Although the implementation details can become complicated, the basic algorithmic framework is quite straightforward and easy to understand.

## The prm algorithmic framework:

• Randomly sample a large number of points in C-space, keeping any that are not in collision. This creates a point set in C-space.
• Using a local planner , attempt to connect pairs of samples that are relatively close to each other by thoroughly sampling and collision checking configurations between them. This creates a graph data structure called a roadmap.
• To query the roadmap, first attempt to connect the start and goal configurations to the existing graph. If that is successful, search the graph for a path from start to goal using any standard graph search method (often A*).
PRM implementations vary in terms of how the points are sampled--remember that random does not mean uniformly at random--as well as in how the local planner attempts to connect nearby configurations.

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
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