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 ...
Bending Unit 22's user avatar
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 ...
50k4's user avatar
  • 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 ...
Chuck's user avatar
  • 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 ...
Chuck's user avatar
  • 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 ...
Petch Puttichai's user avatar
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 ...
Petch Puttichai's user avatar
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 ...
Peter Corke's user avatar
  • 1,692
5 votes
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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 ...
Ugo Pattacini's user avatar
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 ...
Jakob's user avatar
  • 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 ...
James Waldby - jwpat7's user avatar
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 ...
Paul's user avatar
  • 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.
SteveO's user avatar
  • 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 ...
mactro's user avatar
  • 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 ...
hauptmech's user avatar
  • 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 ...
Petch Puttichai's user avatar
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,...
Petch Puttichai's user avatar
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 ...
Chuck's user avatar
  • 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 ...
kamek's user avatar
  • 980
3 votes
Accepted

Check collision between robot and environment in OpenRAVE

It's really easy. ...
Iche's user avatar
  • 304
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 ...
Brian Lynch's user avatar
  • 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. ...
blackcoder's user avatar
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 ...
al-dev's user avatar
  • 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 ...
Greenonline's user avatar
  • 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 ...
combo's user avatar
  • 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, ...
N. Staub's user avatar
  • 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, $\...
Petch Puttichai's user avatar
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, ...
50k4's user avatar
  • 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 ...
Josh Vander Hook's user avatar
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 ...
Peter Corke's user avatar
  • 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 ...
Josh Vander Hook's user avatar

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