29
votes
Accepted
What is the difference between path planning and motion planning?
Compare the following two images:
The path planning is somewhat trivial. There's only one path: the rope. The motion planning on the other hand is not that easy.
In a maze the path planning is hard ...
- 1,425
8
votes
Motion Planning vs. Control
There is a saying in software engineering which states that your company structure is reflected in your software architecture (I cannot recall the exact phrase). This is true for a robot control ...
- 6,652
6
votes
What is the difference between path planning and motion planning?
What's the difference between turn-by-turn GPS and driving a car?
GPS is path planning: high-level commands like, "turn right in 1 mile."
Driving is motion planning, which means following a route ...
- 16k
6
votes
Accepted
rotation matrix to euler angles with gimbal lock
I think you may be misunderstanding the nature of gimbal lock. It sounds like you may be trying to remove an actual term in a rotation matrix calculation , but this is incorrect because each axis is ...
- 16k
5
votes
Accepted
Configuration space of rotating link
Since the configuration space is the set of all possible configurations the link can have, i.e. all possible angles from 0° to 360°, shouldn't the c-space be a line rather than a circle?
You are ...
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5
votes
A* search results in path too close to obstacles
Obstacle padding/ robot padding.
Suppose you are working in a 2D environment and that you have an obstacle of the size 2x2. When doing planning (graph search, etc.), you increase the size of the ...
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5
votes
Accepted
How can Denavit-Hartenberg representation with only 4 variables describe rototranslations with 6 DOF?
In general you need 6 parameters to describe the position and orientation of any joint with respect to a link coordinate frame. The DH parameterisation includes 2 constraints so only 4 parameters ...
- 1,692
5
votes
Accepted
Velocity-Control of a manipulator without a dynamic model
Your intuition is partially correct in the sense that you ought to go with position control implemented via velocity commands resorting to a kinematic (not dynamic) model of the manipulator.
This can ...
- 3,995
4
votes
Line following robot path planning
Line following is a simple reactive behaviour. Before you get into planning to solve the obstacle avoidance problem - which can get quite complex - you should consider simpler solutions.
What this ...
- 3,034
4
votes
Lifting robotic leg with only one servo
Going forward, a Klann linkage has a near-vertical leg drop action. (See the legs at left in the wikipedia animated GIF.)
It has a near-vertical leg lift action if running in reverse. (See the legs ...
- 1,991
4
votes
Accepted
How is homotopy used in planning algorithms?
Let me put homotopy into the context of planning algorithms
Suppose you want to get from point A to point B. Clearly, the easiest way is to traverse a straight line. But if there is an obstacle in ...
- 1,268
4
votes
Accepted
Meaning of symbol, 'curly N' in the equation of Linear Gaussian system dynamics
They are modeling the probability as a normal distribution with the given mean and variance.
- 4,386
4
votes
Obstacle Avoidance while Navigating
I think that vector field histogram method should be a good solution here. It's a method of local motion planning (avoiding local obstacles while navigating to a global target). It involves mapping ...
- 953
4
votes
How can we solve the problem of robot size in sensor based motion planning?
If you are able to sense obstacles with a sensor pattern that is circular (eg laser scanner, contact sensors on a circular body, etc), and you can rotate the robot pose without translation, then you ...
- 4,385
4
votes
Accepted
Math behind trajectory planning
Since the problem is one dimensional, you are actually asking to compute a velocity profile. (A velocity profile is the information of how a path is traversed with respect to time.) Now the problem is ...
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4
votes
Accepted
Motion planning from a given path
Many articles reference algorithms such as A*, PRM or RRT based planners to motion planning algorithms which seems unreasonable since it is still necessary to parametrize found path with time.I wonder,...
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4
votes
Accepted
What is the consquence of Gimbal lock?
I made a clip for you (https://i.stack.imgur.com/Z0q5Y.jpg) using Unity, which internally represents rotations as quaternions, but uses Euler angles for display and positioning.
You can see that, at ...
- 16k
3
votes
Accepted
Suitable D star variant is for non-holonomic motion planning of mobile robots
A brief overview of some of these variants:
A* A variant Dijkstra's algorithm that maintains a heuristic distance to the goal to first explore parts of the graph that are more likely closer to the ...
- 980
3
votes
Accepted
3
votes
What is the difference between path planning and motion planning?
There isn't really a difference. "Path planning" might be used more often to simply describe the problem of finding a desired path from one state (or sub-set of states) to another. Whereas "motion ...
- 1,377
3
votes
What is the difference between path planning and motion planning?
Just an extract from my answer to a similar question:
Path planning is the process you use to construct a path from a
starting point to an end point given a full, partial or dynamic map.
...
- 81
3
votes
RRT algorithm in C++
The OMPL library has some good quality implementations of several sampling-based motion planners, as listed here :
http://ompl.kavrakilab.org/planners.html
In particular, you can find several ...
- 331
3
votes
Accepted
Meaning of s_last in D star Lite algorithm
$s_{last}$ does change.
Looking at the pseudo code, $s_{last}$ is updated upon each iteration of the while loop in main(), in ...
- 1,437
3
votes
Path planning for visual servoing
I would recommend using an RRT or FMT sampling based path planner. The basic idea is to sample your state space and build a tree which connects your starting state to the goal state. Each time you ...
- 440
3
votes
Optimal-Time Trajectory Planning in 1D
Hi usually the time optimal solution of a motion not having specific constraints is know as 'bang-bang'. Where you let you system accelerate and decelerate at the maximum rate possible.
In your case, ...
- 1,402
3
votes
Accepted
Creating linear end effector motion using joint speeds: Converting tool speed to joint speeds
Joint velocities and tool velocities are directly related through the following equation
$$
\dot{x} = J(q)\dot{q},
$$
where $\dot{x} \in \mathbf{R}^6$ is the tool (linear and angular) velocities, $\...
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3
votes
A* search results in path too close to obstacles
Most planning algorithms reduce your robot to a point and plan a path for that point. The arising problem is exaclty what you are facing. As suggested before, obstacle padding is one of the methods, ...
- 6,652
3
votes
What is the difference between Obstacle Avoidance and Dynamic Path Planning?
I have lots of experience with this that I won't bother you with. Most vehicle planners have multiple layers, with different requirements. In short, you're right in that they are very closely related ...
- 5,312
3
votes
Accepted
Is there a Java or mathematical algorithm for Pure Path Pursuit?
In words, rather than code. Assume you have the path defined as a dense list of points.
Find the point on the path closest to robot
Draw a circle of radius R about that point, then find the point on ...
- 1,692
3
votes
Motion Planning vs. Control
I can speak to space robotics, and military-type robotics, and some commercial robots, but there isn't really a "typical" robot yet.
How does motion planning differ from controls?
A drunk ...
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