Questions tagged [geometry]
The geometry tag has no usage guidance.
31
questions
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Get approach vector from Mano hand model
I'm trying to get approach vector/normal from Mano hand parameters that I get from my network. Because the hand parameters are dependent on how it picks an object, I am interested in getting the ...
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1
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52
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Body angle of a centre-articulated robot
Wondering if anyone can help me out with this one, or point me in the right direction. I am working on a centre-articulated robot, which is steered via a push-pull chain drive. The chain drive is ...
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1
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28
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Explanation of the epipolar constraint in stereo imaging
I am watching this video, in which the epipolar constraint is defined as
$x_l \cdot (x_l \times t)=0$
It means that the vector $x_l$ that passes through the observed point and the left camera origin ...
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44
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How to find mathematical model of a wheeled robot (to compute robot's trajectory at given time steps) including its kinematic
I would like to learn, how to find proper kinematic model of robot in mathematical form.
For example:
I would like to create a model of a car, from which I could compute its position and rotation at ...
2
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2
answers
147
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How can I draw a line using rotation of two circles?
I’m building a drawbot with a self imposed constraint that it’s method of motion is just two rotating disks. One holding the paper and one holding the pen. However, the math to calculate the right ...
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given current position and Quaternion and target local rotations (α, β, γ, in radians), how to calculate the new Quaternion
Say we have an object (e.g., end-effector of a robot) that is defined in a general coordinate system by a Cartesian position and Quaternion.
since the Quaternion is with respect to a general and fixed ...
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1
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2
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82
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What is the idea behind calling configuration space a metric space?
In my robotics textbook 1 , the configuration space has been defined configuration space the following way:
A configuration space is a metric space compromising of all given configuration of a ...
user27228
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1
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281
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Bearing landmark localization
I am trying to initialize the position of a set of landmarks using only bearing observations. Each robot pose, described by position (x,y) and orientation (theta), observes a small set of landmarks. ...
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3
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1
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160
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given position and orientation of two coordinate frames, how to transfer a vector from one to another
given position and orientation of two coordinate frames, how can transfer a vector from one frame to another.
The position is given in Cartesian space and the orientations in quaternion or Euler ...
- 151
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0
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114
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How to calculate twist and wrench in local and global frames [closed]
I am rather new to screw theory and also lost in robotics books' formulas. we have a simulator of a robot arm within Mujoco physics engine and I'm wondering how I can calculate wrench and twist in the ...
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410
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relationship between geometric twist jacobian and wrench
I read the robot textbook of Peter Corke and Richard M. Murray, in Peter’s, chapter 8 about jacobian, there are two jacobian, one is geometric jacobian $^0J$ from math, other is world coordinate frame ...
- 187
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Finding orientation angles of end-effector from the DH parameter table and transformation matrices
Let's say we have a manipulator with the following DH parameter table:
and transformation matrices:
$$A_{01}=
\begin{bmatrix}
\cos(q_1) & \sin(q_1) & 0 & 95\cos(q_1)\\
\sin(q_1) & -\...
- 105
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1
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295
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Do I need to use Inverse Kinematics if I have the coordinates of all joints?
So I have the positions of all the joints (x,y,z) of a robot arm. I need to calculate the angles of the joints to feed them to another similar robot arm. I cannot get the angles from the robot I need ...
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136
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Efficient sphere surface area search
As shown in the figure, there are objects of arbitrary shapes placed on the surface of the sphere at arbitrary locations. The problem is to search the surface to locate these objects in most efficient ...
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267
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How to get RPY(Roll, Pitch, Yaw) from directional cosines from a single vector?
I'm trying to find the pose of an 3D vector in terms of RPY. Let's say the two end points of the vector is P0(x0, y0, z0) and P1(x1, y1, z1). So the centered vector I get is V(Vx, Vy, Vz) = P1 - P0 = (...
- 121
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Representation of 2D coordinate space with orientation
I wanted to know what is the mathematical representation of 2D coordinate space with orientation in the same plane.
2D coordinate space is represented as $R^{2}$, how do I include orientation in the ...
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315
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Vısual sensor.camera lenses with a field of view of more than 180 degree
What kind of camera models can be used for lenses with a field of view of more than 180 degree ?
Is ıt possible if not why?
Are fisheye lenses suitable for this purpose?
- 186
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1
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2k
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Image coordinate to robot coordinate
I am working with a Nao robot. One if the things I want to do is the following:
Take an image of geometrical objects in front of the Nao (done)
Extract features from the objects in the image, such as ...
- 121
1
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0
answers
87
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Which Trajectory representation for optimization
I'm strugling on that problem for a while, so any help is welcome.
I need a trajectory representation that is performant for optimization, i.e. I want something that computes quickly. The function I ...
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1
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44
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Recognizing a line from three r-theta ultrasonic distance readings?
Anyone know of sample Python code, or a tutorial, on the polar coordinate math for recognizing that three ultrasonic distance readings form a straight line?
...
2
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0
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94
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Consitent Scale in Monocular pose estimation
I just wanted to know if scale is conserved across multiple images, when doing a process such as monocular odometry. I know in reality the scale tends to drift over time due to accumulation of small ...
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2k
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6 axis robot arm with non-perpendicular axes?
Lately I've been thinking about 6 axis robots and noticed that all examples that I've seen on the internet use the same configuration of axes:
Vertical axis waist (1), horizontal axis shoulder (2) ...
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3
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2
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97
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Fence avoidance for manually controlled robot
I'm trying to find known techniques for keeping a manually controlled robot within a known polygon fence. More specifically, a pilot controls a robot by issuing desired velocity vectors, and the ...
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3
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2k
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Generalized Voronoi Diagram
I need to compute the Voronoi diagram for a map with some obstacles but I can't find any pseudo-code or example in MATLAB.
The "voronoi" function in MATLAB works with points, but in this case the ...
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3
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1
answer
150
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Mobile robot algorithm implementation error
I am working in reproducing a robotics paper, first simulating it in MATLAB in order to implement it to a real robot afterwards. The robot's model is:
$$\dot{x}=V(t)cos\theta $$
$$\dot{y}=V(t)sin\...
- 65
1
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0
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47
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How to determine the angles between a UAV and a sphere
I have an UAV modeled in three dimensions with let's say position coordinates $p_{uav} = (x_1,y_1,z_1)$ that is moving in a direction $d = (d_x,d_y,d_z)$ and a moving obstacle modeled as a sphere with ...
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4
answers
2k
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Most accurate rotation representation for small angles
Assume that I have a rigid body for which I know that it can rotate with respect to a global reference frame (which is considered fixed and already given) for only a few degrees of angle, so I can ...
- 129
2
votes
2
answers
228
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Angle to a circle tangent line
I want to simulate the detection of a moving object by a unicycle type robot. The robot is modelled with position (x,y) and direction theta as the three states. The obstacle is represented as a circle ...
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1
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41
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Which geo-projection to use for odometry [closed]
I would like to make a little survey regarding the (geo)spatial projection that you use when elaborating your GPS and movement data for the spatial awareness of your robots.
Moving all GPS ...
- 113
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112
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6D localization with 6 lasers
I have to know where a multi-rotor is, in a rectangular room, via 6 lasers, 2 on each axis.
The problem is like this:
Inputs :
Room : square => 10 meters by 10 meters
6 positions of the lasers : ...
- 181
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1
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281
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Relative orientation of two robots
Given two robot arms with TCP (Tool Center Point) coordinates in the world frame is:
$X_1 = [1, 1, 1, \pi/2, \pi/2, -\pi/2]$
and
$X_2 = [2, 1, 1, 0, -\pi/2, 0]$
The base of the robots is at:
$...
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