Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CSCI 4341 > Lecture 8: Motion Planning > Flashcards

Lecture 8: Motion Planning Flashcards

1
Q

In the section of Representation, what is workspace?

A

is often the representation of the world, possibly independent of the robot itself. Often describes some notion of reachability, what space is free or occupied?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In the section of Representation, what does configuration space describe?
(the f sta of the rob in the w)

A

the full state of the robot in the world (actuator positions, orientation, etc.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Positions in configure space tend to be?

A

Close together for the robot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Using configure space can make it easier to do what 2 things?
(Solving coll checks, join nrby poses)

A

Solve collision checks and join nearby poses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Configure space allows a level of abstraction that means?
(Sol meth can s a wider r o p)

A

solution methods can solve a wider range of problems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is very common to do after converting a planning problem to some kind of graph?

A

use one of a variety of existing search algorithms on the graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What 2 things are structured?
(OccuGr, DisFiel)

A

Occupancy Grids and Distance Fields

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What 3 things are structured
(PoiClou, Mesh, Exa)

A

Point Clouds, Meshes, Exact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What has both unstructured and structured

A

Graphs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The edges of a directed graph have ?

A

direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The edges of a weighted graph have? (c)

A

costs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does Discrete State Space Representation do to Continuous State Space?

A

reduces it to a finite set of discrete states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When ti goes from a grid to a graph, what are states and transitions considered?
S as v, T as DE

A

States as vertices; transitions as directed edges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the process of a graph?
(Xs, Xg, X*A–>R^+)

A

Add a start node(Xs), goal node(Xg), and cost function(C: X*A→R^+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can be treated as a graph search problem?

A

Finding the shortest path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 4 issues with grid-based representation?
(loss of precision,
appropriate grid res,
limit output path,
poor scaling in higher dim)

A

suffer some loss of precision, selecting an appropriate grid resolution, limit the type of output path, poor scaling in higher dimensions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you create a grid lattice?
(Cre,Constr)

A

first make a set of feasible motion primitives and construct a tree/graph that chains the motions into a sequence/plan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does a visibilty graph create between all pairs of mutually visible vertices?
(e)

A

edges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Is visibility the optimal plan?

A

Yes

20
Q

What graphs require careful consideration to construct graphs with guarantees?
(R-S Gra)

A

Randomly-sampled graphs

21
Q

Randomly-sampled graphs are popular for what?
(S-based meth)

A

sample-based methods

22
Q

3 steps to solve planning problem
(Conv prob, srch, pro)

A

Convert problem to graph
Search the graph
Profit!

23
Q

What edges are generally considered in graph search?
(+)

A

positive edge weights

24
Q

What are the 4 graph search methods?

A

BFS, DFS, Dijkstra’s Algorithm, A*

25
Q

In OPEN SET, what are the 4 characteristics?
(Maintains a list of frontier …
Keeps track of what ….
Often stored as a ..
For each n, know at least 1)

A

maintains a list of frontier (unexpanded) plans
Keeps track of what nodes to expand next
Often stored as a priority queue
For each node in the open list, we know of at least one path to it from the start

26
Q

In CLOSED SET, what are the 2 characteristics
(Set keeps track of …..
For each n, found l-c p)

A

set keeps track of nodes that have been expanded
For each node in the closed list, we’ve already found the lowest-cost path to it from the start

27
Q

Time complexity of Breadth-first search?

A

O(|V|+|E|)

28
Q

What guarantees to find the shortest path?

A

BFS

29
Q

How does DFS search?

A

starts at the root node and explores as far as possible along each branch before backtracking; has a stack queue

30
Q

What has a lower memory footprint: BFS or DFS?

A

DFS

31
Q

Is DFS complete for infinite trees?

A

No because it may explore an incorrect branch infinitely deep, it may never come back up

32
Q

Dijkstra’s algorithm was published when by who?

A

Edsger Dijkstra in 1959

33
Q

Basic idea of Dijkstra’s algorithm?
(expanding in ord of c - st)

A

expanding in order of closest to start (BFS with edge costs)

34
Q

What is Dijkstra’s algorithm known as
(asymp the fast.. known s-s p algo for arbitrary dg)

A

Asymptotically the fastest known single-source shortest path algorithm for arbitrary directed graphs

35
Q

Manhattan Distance and Euclidean Distance are examples of what?

A

A* Heuristic Search

36
Q

What is the equation of A* Priority?

A

f(n) = g(n) + h(n); g(n) is the cost to arrive and h(n) is the heuristic cost to goal

37
Q

3 Valid Heuristics

A

Euclidean Distance,
Manhattan Distance,
Zero(Dijkstra’s algorithm)

38
Q

What are the 3 limitations of A* Search?
(need to …..,
sometimes and admissible heu func is diff to f,
not good rep of prob)

A

You need to construct a graph
Sometimes an admissible heuristic function is difficult to find(as hard as the problem)
A grid may not be a good representation of your problem

39
Q

2 types of uncertainties?

A

Environment uncertainty, Motion uncertainty

40
Q

Are potential field methods relatively simple to implement?

A

Yes

41
Q

What do Potential fields design?

A

a function such that descending the gradient leads to a collison-free path to the goal

42
Q

What are two examples of hierarchical planning?

A

Global planner over the whole search space
Local planner to respond to changes in environment, avoid collisions, stay on global path

43
Q

Graphs are constructions of what two things?
(vert and CE)

A

vertices and connecting edges

44
Q

Configuration space is what?

A

the robot’s configuration(joint angles etc) in the world

45
Q

What is work space?

A

the world without the robot

CSCI 4341 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions