Questions tagged [motion-planning]

Motion planning (also known as the navigation problem or the piano mover's problem) is a term used in robotics for the process of breaking down a desired movement task into discrete motions that satisfy movement constraints and possibly optimize some aspect of the movement.

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38 views

motion model for forward movement

I thought this is a simple and well known problem and therefore there is a lot of literature. But I'm not able to find the correct keywords to google the answer. Maybe instead of answering the whole ...
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Applications of Reinforcement Learning

Many global-control applications of robotics involve incomplete world information and at best can be represented as a POMDP. Given this, can we really apply RL to most robotics applications? From ...
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Link collision avoidance for redundant manipulator

I am trying to have my robot arm follow a trajectory while avoiding collisions between obstacles and the robot links. The way I go about it is to find the closest point on the robot arm, and treat the ...
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Navigation Function : Sphere Spaced Set

The navigation function in a sphere spaced set is given by: Equation How do I determine the value of Lambda?
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discrete control in continuous spaces

I asked this question on AI stack exchange but didn't get a response. Basically I'm interested in how you deal with inherent error between your ideal discrete state and your actual state in control ...
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51 views

Asynchronous axes movement

if we have a robot with 5 DoF and we want to plan its movement. The inverse kinematic solver will do this job without a doubt. However, it is usually assumed that axes can be moved in a synchronized ...
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How to find the optimal path for a line following maze robot?

First let me explain the problem. This is a maze made only out of black lines on a white surface. The robot has only a few IR sensors which can sense the position of the line. No other sensory input ...
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39 views

Problem with solution (equation) for wrist singularity

In my textbook about industrial robots it says that if the angle q5 in this robot is equal to 0, there are infinite solutions for the angles q4 and q6. I understand this part, but I have a problem ...
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26 views

How to deal with a joint suddenly having to make a large change in angle during linear interpolation?

After having set up the inverse kinematics for each intermediate point on a line that the tcp is supposed to travel, I encountered a problem that stops the tcp when it is supposed to travel along the ...
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73 views

Going from Spline to Differential Drive Command

I have a differential drive robot that needs to move along a path stored in its memory as a spline. I am currently trying to understand the mathematics of determining how much power to apply to each ...
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Doubt on artificial potential field

I am studying motion planning, and I am focusing on artificial potential fields. I have seen that it consists in having a repulsive field for obstacles, and an attractive field toward the goal. But ...
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When do I do motion planning?

I am studying mobile robots, and I am focusing my attention to the unycicle. I have a doubt concerning the motion planning part. In particular I don't understand when the motion planning is done and ...
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Construct Configuration-Space with Obstacles for arbitrary Object/Robot in Motion Planning

I found that a configuration-space approach is a elegant way to describe problems in motion planning. However, I was not able to find a known general way to construct configuration-spaces. By general ...
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Motion Planning vs. Control

Often I see positions for robotics companies split into planning and controls engineers. But motion planning and controls seem to have a lot of overlap. As I understand in motion planning the ...
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Moving Sofa Problem with the help of 'Potential Field Method' and 'Navigation Functions'

I would like to move a piano. Having a mathematical background, I was trying to figure out whether I can get it into the new apartment. In my research I stumbled upon the already explored "moving sofa ...
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37 views

Can knowledge of robot's dynamics help in motion planning?

Some planners assume a kinematic model of the robot for example diff drive or omni directional etc. while generating motion plans for the robot. Can knowledge of the dynamics of the robot help ...
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Path Planning algorithm

The broad question is this; given an occupancy grid and the robots current pose (x,y,theta,theta'(first derivative)) how should I plan motion for my robot with the following constraints: shortest ...
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Automatic forward and reverse Brushless Motor

The video Here shows a motor using rotational motion to move a load forward and then reverse back, without manually switching it to reverse. How can I program my brushless motor to operate like the ...
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196 views

moveit! trajectory execution aborted

I'm trying to send a custom arm to a pose through moveit_commander_cmdline.py, it fails after sending to the said pose using " go default_pose" and returns an error. ...
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Occupancy grid mapping

I want to construct 2D occupancy grids for mapping of an unknown environment. Could you guide me how can I achieve it? What I have researched is that robot can construct its map given sensor data ...
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37 views

Planning minimum snap trajectories

I am working on motion planning algorithm for quadrotor. As I have learned in Coursera Aerial robotics course, trajectories for quadrotors should minimize snap which is equivalent to interpolating ...
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Statistical distance between degenerate distribution and any probability distribution

In sample-based motion planning, sampling methods would change the cost of path and computation time for the same planning algorithm. I would like to compare different sampling methods. So, the ...
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77 views

Given an initial position, a goal position and a duration find a trajectory

I have an initial position $X^R_{init}$ of the robot ($x$, $y$ and yaw) and a goal position $X^R_{goal}$ I need to create a trajectory of duration $T$ with $n$ waypoints to move the robot from its ...
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123 views

Is there a Java or mathematical algorithm for Pure Path Pursuit?

I was building a robot which I wanted to have smooth consistent motions and pathways. I am somewhat familiar with Pure Path Pursuit and wanted to know if someone could point me towards a mathematical ...
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137 views

How can Denavit-Hartenberg representation with only 4 variables describe rototranslations with 6 DOF?

I am wondering how the Denavit-Hartenberg representation is able to describe rototranslations with 6 DOF with only 4 parameters? Some context: Denavit-Hartenberg representations can be used to ...
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Interference caused by multiple robots during task completion

Suppose there is an area to survey. If we deploy one robot it takes time T to sweep the area. Now if we deploy 2 robots, we would expect it to take time T/2. However in reality, because we are sending ...
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667 views

Difference between Single-Query and Multiple Query Algorithms?

I am spending a lot of time in understanding these two concepts, because in several papers that I read, they define them differently, and I do not know exactly what is the meaning of the two different ...
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URScript - how to get the actual TCP pose in tool space coordinate system?

I am writing a simple script for universal robots UR10 robotic arm. I am trying to find a way to to see if the tool current position is outside of a 3D bounding box. the 3D bounding box is defined ...
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90 views

Controlling YuMi robot by serial port

I'm trying to control the YuMi robot arm by a serial port. The serial port will give the information on what direction the end-effector should move and what is the velocity. What I would like to ...
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Trajectory following- What if the robot joint motor are not able to keep up with the generated trajectory?

I want my robot manipulator to follow a user-defined path. Based on the waypoints given as input and the velocity and acceleration limits of the joint motors, I generate a trajectory. At every time ...
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170 views

What is the difference between Obstacle Avoidance and Dynamic Path Planning?

I always assumed that obstacle avoidance refers to general prevention of collisions with any kind of obstacles, even without considering a goal for the decision how to execute an avoidance maneuver. ...
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210 views

Difference between Collision Cone and Velocity Obstacle

I'm trying to understand these two classic approaches to path planning in dynamic environments/with moving obstacles. According to some review papers, there seems to be quite a difference between them,...
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74 views

Path planning of wheeled robot [duplicate]

let's say the robot Looks like this (an usual robot arm with 4 wheels) : In this case as far as I know, the idea of path planning is just to compare the actual position x with the desired position ...
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151 views

A* search results in path too close to obstacles

I have a configuration space as below with several obstacles. Green circles are all the points I need to go to. Blue line is the path returned from A* search. However, I am looking for path that's ...
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153 views

Incremental (on-the-fly) smooth trajectory interpolation algorithm from waypoints?

short version (TL;DR): I'm receiving x(t) waypoints "online", which I must travel through at the specified times. I need an algorithm that would plan a smooth trajectory in-between them without ...
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94 views

EKF Slam algorithm doubt at observation update

I have some doubt on EKF Slam with known correspondence in the measurement update state. I follow the algorithm from Probabilistic Robotics by Sebastian THRUN. This Algorithm is on Chapter 10 page No:...
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RRT star Convergence

My Code gives the following convergence characteristics, I wanted to know if it is correct Updated code { ...
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163 views

Creating linear end effector motion using joint speeds: Converting tool speed to joint speeds

Background Information: I'm new to robotics and my school currently has access to a 6DOF Universal Robot (UR-10). I'm programming it using its scripting language URscript and the arm has these two ...
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433 views

How can I get the right sample in RRT star Dubins?

I am trying to find a solution in S(1)*R^2 (x,y, orientation) with obstacles (refer to image) using RRT star and Dubins Model. The code takes a lot of time to find a suitable random sample with x,y, ...
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71 views

Math behind trajectory 2d planning

I have a case of a differential drive robot and a control system in a two-dimensional environment: Now the problem: we would like to make our particle move from point A to point B, and from there to ...
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130 views

How to increase the payload for the KUKA arm with KR210 claw?

https://github.com/udacity/RoboND-Kinematics-Project We are using the above mentioned KUKA arm model to simulate pick and place. We noticed that KUKA arm would not pick objects heavier than 2.5 kg in ...
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Orientation problem between Gripper and Object ??

I am working on a pick and place project using ROS & MoveIt!, I wrote my own pick and place functions which generate grasp poses according to the pose of the object and then automatically picks. (...
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421 views

How to plan path for robotic arm with RRT?

I have written simple RRT planner however I am not sure how to apply it to a robotic arm path planning. The issue is that of analytical solution absence to inverse kinematics problem. Let me explain. ...
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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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509 views

Are S-Curve (constant jerk) motion profiles significantly better than constant acceleration?

I've been investigating S-Curve motion profiles for CNC router and 3D printer applications, and haven't come across any definitive source that says an S-Curve profile is necessary in any application. ...
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Optimal-Time Trajectory Planning in 1D

I have been searching for a solution to the mentioned above problem, but nothing was accurate enough. I am trying to find the optimal-time trajectory for an object from initial point A to final point ...
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210 views

Configuration space of rotating link

I have only recently started reading Steve LaValle's book on motion planning. It mentions that a rotating link with a fixed pivot has a configuration space of a unit circle. Since the configuration ...
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362 views

Project ideas for Robot modeling

I am a 1st-year grad student majoring in robotics. I have the opportunity to select and execute my own projects for a course called Robot Modeling. For the project, I have decided to model a UR5 and ...
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Is there a formal name for translating poses into robot states?

I've been working on a module that takes in planar poses $\begin{bmatrix} x_{t_{k}} & y_{t_{k}} & \theta_{t_{k}}\end{bmatrix}^{T}$ and spits out expected robot states $\begin{bmatrix} x_{t_{...
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Getting started with motion planning

I have recently finished the coursera Motion Planning course and I am looking for a project to do, using ROS, OpenRave, Gazebo and similar tools. My project would be in the area of motion planning for ...