Questions tagged [rotation]
The rotation tag has no usage guidance.
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Ball bearings size for an RC car
I'm want to build my first RC vehicle and for a few days I'm trying to choose the size of the ball bearings for the wheels. I'm planing to use 2 per wheel. Are 5x10x4mm (inner/outer/depth) going to ...
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How do we derive the loop closure equations?
Looking to derive these equations. I don't intuitively understand what it means to take a cos of two independent angles added together. Nor do I understand why all of these are equal to 0. It is hard ...
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Siciliano et al. Rotation Matrix Notation
I'm reading Siciliano et al.'s Robotics: Modeling, Planning and Control, and I'm confused about the notation used in definiting rotation matrices.
On page 46, they state
If $\textbf{R}_i^j$ denotes ...
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Calculation of IMU offset for Placement of Inertial measurement unit away from centre of mass
I am working on a 6DOF IMU that contains a 3-axis accelerometer and a 3-axis gyroscope. I am building a project to plot the position and orientation of a vehicle/dirt bike in a 3d plane. However, the ...
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Center of gravity offset for accelerometer and gyroscope readings
I am working on a 6DOF IMU that contains a 3 Axis Accelerometer and a 3 Axis Gyroscope.
I am building a project to plot the position and orientation of the turret/cabin in a crane in 3D space.
The IMU ...
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Rotate sensor frame to body frame
I'm working with a lsm303agr from ST. Here is the frame attached to the chip
Here is the body frame
So I have some doubts about the rotations, before to fuse data ...
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Get a rotation to align a vector, n with another vector, a and be able to rotate around a
Let us say I have a rigid body, B. Let us say I have a normal vector n. And let us say I have another direction vector a. I need ...
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geometric meaning of rotation matrices related to different frames
Consider the following rotation matrices:
$^{a}R_{b}$, $^{a}R_{c}$ and $^{a}R_{d}$
in which
$^{x}R_{y} \in SO(3)$ describes the orientation of a generic frame $y$ wrt the coordinates system of ...
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transform IMU reference to robot reference
I have an IMU rigidly attached to the end effector of a robotic arm. The goal is to compare the orientation of the IMU to the orientation of the robot arm. The 9-axis IMU data is used in a sensor ...
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Using an IMU to determine the axis about which it is being rotated
I've got a 6DOF IMU and have, using some trig and and a few references such as ADI's app note: https://www.analog.com/en/app-notes/an-1057.html successfully implemented some Arduino/C code to ...
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Finding a point in a new reference frame <modern robotics>
From modern robotics chapter 3.2 and figure 3.7, how do we obtain $p_{b}=\begin{bmatrix}1 & -1 & 0\end{bmatrix}^{T}$ from $R_{b}$ and $p_{a}$? Because $R_{b}*p_{a} =\begin{bmatrix}-1 & 1 &...
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Get rotation of IMU data snapshot
I received snippets of data of an IMU with 9 DoF in motion. For these I wanted to get their rotation by angles relative to the earth frame. My goal is to receive ...
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End effector rotates 180 degrees when trying to set orientation with direction vector
I want to orient the robot endeffector using a direction vector that I calculate myself. The robot will always start from the same position with the endeffector pointing straight down. I already have ...
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Can you increase resolution/accuracy by mechanically averaging two actuators?
I'm working on a project using hobby servos to drive a revolute joint, and the servo mechanism doesn't seem to respond when I command a motion of less than about 1 degree. I want to increase the ...
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How do you rotate positions from ENU-frame to body frame?
If positions are in the local frame of ENU (or ECEF - either works), how do you rotate that to the body frame of the device?
Logically, I thought that I could use the pitch, roll, and yaw angles of ...
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Mapping IMU readings from body frame to navigation frame
I'm trying to combine IMU displacements with the time of flight sensor readings in order to navigate through the indoor environment with a non-linear Kalman filter variant. In the graphic below, I ...
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Aligning accelerometer readings with vehicle's frame of reference
I have a device with an accelerometer installed in a vehicle. Its orientation in relation to the vehicle is unknown. So I am looking for a reliable way to align the coordinate system of the ...
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What is the consquence of Gimbal lock?
I'm learning about Gimbal lock and I understand the reason why that happened.
But I don't understand why that is a big deal because it only affect this rotation. After this rotation finished, we have ...
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Why do we parametrize matrices?
I'm learning about rotation matrices in class and one of the topics mentioned to parametrize a matrix.
What do we need to do this?
For further reference: https://www.youtube.com/watch?v=Y8gB7nvtmrU
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Relative rotation and a new reference frame as the rotation of the first object
this is my first post on this forum
I have $n$ IMUs which outputs its rotation their matrices in the $XYZ$ world coordinate system $w$. I would like to use multiple IMUs $n$, such as $n_{1}, n_{2}, n_{...
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Confusion about Gimbal lock
I am trying to understand exactly what is happening when Gimbal lock occurs. I have read many explanations now which provide the high-level idea, in that Gimbal lock occurs when two axes are aligned ...
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Multiplication of rotation matrix help
I'm Watching Angela Sodemann video on 6DOF robots and am following her example, but I'm getting a different answer for my R3_6 matrix and I'm not sure where I'm going wrong. She uses this as her ...
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How to get odometry from propeller rotation signals knowing that they can rotate to maximum value?
m trying to get Velocity in order to control underwater swarm ROV. I can use the acceleration and to Euler integration but the error will be accumulated over time. As we are having a swarm (many small ...
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How to measure an optical encoder resolution and gear ratio?
I've bought a DC geared motor with an optical encoder. The vendor didn't provide specification. I can read MITSUMI M25N-2R-14 2241 and 25GA-370-12V-330RPM on the motor. There are some pages on the ...
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Multiple Rotations via Matrix Multiplication
so I am having an issue understanding why you right multiply for current frame rotation vs left multiply for fixed frame.
Let us say you want to: Rotate about x, then Rotate about current y, then ...
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How to avoid gimbal with Quaternions
I'am working with an LSM6DSO32, so I'am starting with Kalman filter, everything works but with Euler angle I got gimbal lock I think... But if my pitch angle approach to 90° my roll angle jump and I ...
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Can the tangent space vector of SO3 be interpreted as Euler angles?
I want to compare the rotation of two cameras with respect to a common frame. Let's call these R_World_Cam0 and R_World_Cam1. ...
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What type of electric motor and speed-controlled circuit do I use to bounce a hanging, 5 pound weight? (it's for a Halloween decoration)
I'm trying to make a roughly 5 pound, hanging halloween decoration bounce on a string from about 1-3 times per second, preferably at variable speeds if I can.
I've looked up a simple DC motor circuit ...
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Inertial frame's angular velocity expression
I'm following a robotics course on coursera which talks about aerial robotics and more specifically quadrotors.
I'm trying to understand the logic behind the relationship between the angular velocity ...
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Calculating rotation matrix efficiently
I'm trying to efficiently calculate the vertical offset of each corner of a rectangular base. I have an accelerometer mounted in the middle of the base, ADXL345. The steps I have taken, and seems to ...
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How to handle robot movement close to coordinates x=0 with atan2
I am working on controlling a robot to various points on an x,y grid. The robot starts at random locations and I can control it's velocity and angular velocity.
Currently, I am using the technique of ...
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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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How do I calculate components of an angular rate on end effector frame?
I’ve helped develop the forward kinematic chain for a two-axis gimbal. The Denavit-Hartenberg parameter table for the kinematic chain is given below.
$\theta$
$\alpha$
$r$
$d$
$90^{\circ}$
$90^{\...
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IMU Change of reference frame
Im trying to rotate one accelerometer vector from body frame to ned frame, but i cant found what im doing wrong. For now, im using an online dataset that provides me roll, pitch and heading ...
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How to make two frames relative to each other
I have a Velodyne and camera that both have transformations specified relative to the origin of the robot.
The original transformations were specified as yaw, roll, pitch, x, y, z. I wrote a script to ...
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Rotate while strafing with mecanum wheels
I have a robot with a drivetrain that is comprised of 4 mecanum wheels. These wheels are able to move vertically and horizontally, as well as rotate. The robot is square (18in x 18in) with the front 2 ...
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What type of rigid body rotation can best be learned by neural networks?
I am training a reinforcement learning network in simulation for a robot which at the current stage learns Euler Angles to rotate the end-effector based on the actual state. The performance is overall ...
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What could cause quaternion error to go up drastically when a gyroscope is rotated on more than one axis at a time?
Alright, I'm working on a small Arduino script that determines orientation using a a gyroscope and a quaternion. My hardware:
LSM9DS1 IMU (Gyroscope, Accelerometer, Magnetometer)
Teensy 4.0
My basic ...
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Does every rotation vector has an one-to-one corresponding rotation matrix?
Given a rotation vector, can we always get the same corresponding rotation matrix computed by the Rodrigue's rotation formula?
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Compute path in absolute frame from sequence of measurements
I have a sequence of measurements $\{(x_i, y_i, \theta_i)\}_{i = 1 \:...\: N}$. Each of these represents the new pose of the robot seen from the previous pose, i.e. a measurement $(x', y', \theta')$ ...
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Motion model and homogeneous transformation issue on a drone
I am trying to develop a EKF-SLAM algorithm for a drone, and I want to estimate its position in the inertial/world reference frame. I have as control variables the linear and angular velocities in the ...
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Conveyor Belt Calibration for a Robot - Rotation Matrix
Short Question:
As demonstrated in the image below, how can I calculate the rotation matrix that relates the base coordinate and the rectangle coordinate, given 3 known points P1, P2, P3 on the ...
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what are shoulder ball and socket joints called? (i am trying to design and build a hydraulic assistance mech suit)
I'm having problems finding the right sort of joint for my shoulder connection. It is a flat surface on the side of the mech body and I need to create a joint with maximum movement rotating: up, down ...
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Understanding Twists as 3D Velocities
I am just learning about twists to represent 3D velocities (e.g. of a robot's end-effector), and I have two questions:
1) Wikipedia defines a twist as "an angular velocity around an axis and a linear ...
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How to calculate rotation angle from 3D points
I have 4 3d points(x, y, z). Using these points how can I calculate rotation angle? Consequently, I want to have a 4x4 transformation matrix including rotation and translation information.
4 points ...
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Rotate coordinate frame using 2-axis inclinometer angles
How to rotate coordinate frame (transform point or vector coordinates) using angles from 2-axis inclination sensor if both X and Y angles are non-zero?
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Doubt about axis\angle representation
I am trying to understand the axis/angle representation.
So far, I have understood that the main idea is that every rotation can be represented as a rotation around an arbitrary axis of an angle $\...
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Reset coordinate system of robot while maintaining relationship to the previous
I am currently estimating a robot's pose (3d position and rotation matrix) with an IMU and I want to reset the localizer in the middle of the run while keeping the relationship to the pose it had when ...
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What is my last rotation matrix for the last three angles when i have found the first three when doing inverse kinematics to a 6dof robot?
I am doing inverse kinematics for a 6dof robot.
I have used the geometrical method to describe the angles from one to three. I have trouble doing the next part. I know I that I have found the ...
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Finding quaternion Q, where Y = q * X * q.inv()
Problem
Quaternions $X$, $Y$, which represents 3-dimensional points are given.
Quaternion $q$ is what is to be solved.
I want to know unknown rotation between $X$ and $Y$.
In other words, I want to ...
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