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Questions tagged [rotation]

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1answer
23 views

Observed position update after motion of the robot

The equation (14) in this paper, $$ P_{Cj}=RP_{Pj}+T+e_j $$ where $P_{Cj}$ and $P_{Pj}$ are the observed positions of feature $j$ prior to and after the current robot motion, $R$(otation) and $T$(...
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0answers
13 views

Undo pitching effect of camera when pose (y-axis) is near 90 degrees?

I am using KITTI odometry dataset whereby the camera's axis is pointing X (east), Y (down) and Z (north). It also contain the frame to frame poses of the camera (first pose is fixed as the map frame). ...
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1answer
17 views

How should I create a Pangolin (Armadillo) structure?

I am new to this forum. I want to create a mechanical structure as depicted in the image A pangolin bag. And further wouls like to automate the closing and opening of the bag. But I am facing issues ...
5
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1answer
40 views

Adjusting the PWM frequency and duty cycle to achieve the desired angular velocity in differential drive robots

I am practicing C++ and intro to robotics using a simple differential drive robot and a raspberry pi. Also following along the GA Tech course on control of mobile robotics. The implementation I am ...
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2answers
90 views

Finding correct RPY for approaching a known point on a plane

I have a robot with 6 DOF that I want to use to grab a hanging sheet at a specific point near its edge. The grip needs to be perpendicular to the edge and co-planar with the point of course. I have ...
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1answer
58 views

How can I attach an arm to a double-flat drive stepper motor?

This is my first robotics experience, outside of one class 10 years ago. I've been Googling this question for about an hour but I can't find an answer! I'm using a ROHS Step Motor 28BYJ-48 (with an ...
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3answers
77 views

Forward Kinematics with matrices

From the image, I would like to find out how joint 1, 2 and 3 can be computed by using forward kinematics? (Assuming a theta value was given) I understand that to get point 3 to origin (...
3
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1answer
140 views

Using pre multiply or post multipy for rotational matrix to get a new homogenous transformation matrix?

I am confused about how do I multiply the rotational matrix in this case. I know that both T1 and T2 needs to be multiplied by a rotational matrix but I don't know how to multiply the rotational ...
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2answers
58 views

Why Euler Angle is set to be in ZYZ order?

We have 3 DOF for rotation in 3D space. So to describe an arbitrary rotation, we need to describe its 3 DOF. Euler angle does this by dividing a rotation in 3 steps, first rotate along the Z axis of ...
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1answer
145 views

Get Yaw from quaternion

I found a formula online to extract yaw from a quaternion like so: ...
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0answers
54 views

Equivalence of Alias and Alibi interpretation of Rotation Matrices [closed]

Let's consider two right handed frames $\mathcal R_A$, with coordinate axes $i_A$, $j_A$ and $k_A$ and $\mathcal R_B$, with coordinate axes $i_B$, $j_B$ and $k_B$. Defining the rotation matrix $R^A_B$ ...
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3answers
115 views

A closed-form solution of $\textbf{R}\textbf{R}_1=\textbf{R}_2\textbf{R}$ w.r.t $\textbf{R}$

Is there a closed-form solution of $\textbf{R}\textbf{R}_1=\textbf{R}_2\textbf{R}$ with respect to $\textbf{R}\in SO(3)$? $\textbf{R}_1$, $\textbf{R}_2 \in SO(3)$ are given. Added: I tried holmeski'...
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1answer
65 views

SE3 composition operator gives unexpected results

Given Data and Algorithm I have a stream of SE3 poses supplied by a basic wheel encoder odometry through ROS message passing system. Odometry publishes data in traditional to ROS ENU coordinate frame ...
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1answer
39 views

Angular velocity vector expression uncertain?

I have this problem of an excavator from a test I took a while ago. Frame $\underline{\vec{e}}^0$ is the origin. Frame $\underline{\vec{e}}^1$ rotates around $\underline{\vec{e}}_{3}^0$ with angle $\...
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2answers
51 views

Nested Rotation of a point around arbitrary vector in 3D

I have a point (x,y,z) in the 3D space. This point rotates by theta1 about the arbitrary axis ax1. This axis (ax1) rotates by theta2 about another axis ax2. What will be the new coordinates of the ...
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1answer
129 views

Solving Inverse Kinematics with unknown orientation

This may be a very basic question, but I haven't had much success finding an answer. I'm currently trying to solve the inverse kinematics of a 3-RRR Planar kinematic arm, whose purpose is to move ...
0
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1answer
171 views

Rotation composition When using Kalman Filter

I am implementing a Kalman Filter for the following situation. I have a camera set in a room that can detect the position and orientation of a marker (ARUCO) in the room. Therefore I have the ...
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1answer
629 views

How to rotate a rotation quaternion in the body frame to a rotation quaternion in the world frame?

I have a sensor (3 axis gyroscope) which can rotate and measure angular velocity in 3 dimensions (aligned with the sensor). I know what its current orientation is with respect to the world frame. Call ...
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2answers
84 views

Explanation for exponential coordinate of rotation

From figure above, suppose a three-dimensional vector $p(0)$ is rotated by an angle $\theta$ about the fixed rotation axis $\omega$ to $p(\theta)$. Here we assume all quantities are expressed fixed ...
0
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1answer
27 views

router tilting mechanism

I am trying to design a very rigid tilting mechanism for my router. For this purpose I had a look at table saws, which seem to be supported by 2 mechanisms, one in front, one at the back, called "...
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2answers
149 views

How to reduce the small free rotation/movement of a stepper motor shaft?

I was successful in running a 28BYj-48 stepper motor with 4096 steps per revolution. I am happy with the result. But there is a free movement of the motor shaft itself - you can move the motor shaft ...
1
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1answer
62 views

integrating perfect rate gyro data (noiseless)

Having a perfect gyro (with no noise/drift or bias), the gyro produces angular velocities in the form (wx, wy, wz) in rad/sec. I would like to convert the rate gyro readings (which are expressed in ...
1
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1answer
48 views

Ignoring yaw for pick and place

I get an object pose from the camera in quaternion. Since these are tetrahedron shaped objects, the robot needs to align the vacuum gripper to one of the sides of the object. But the yaw (rotation ...
0
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1answer
646 views

forward and inverse kinematics of arm

I'm trying to figure out to a problem with a planar manipulator. The manipulator has a base effector and L1 and L2 with 3 joints. Question: INVERSE KINEMATICS Given the ...
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1answer
291 views

Orocos KDL issue with Rotation (matrix) - Inverse Kinematics

I have a problem with the Orocos IK solver, especially with the KDL::Rotation matrix input. I try to call my KDL IK solver with a normal vector and a rotation. If I use the example values for the ...
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1answer
78 views

Convert Twist from frame B to frame A [closed]

(full disclosure: this is homework) I have a twist expressed in frame B: $\zeta_b = \begin{bmatrix}1\\3\\-2\\0\\-2\\4\end{bmatrix}$ And a general transformation matrix: $g_{ab} = \begin{bmatrix}-0....
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1answer
53 views

Calculate Transformation between two point sets - but with constrained Degrees of Freedom

How can I calculate the rigid-body transformation [R|t] between two 3d triangles, but restricted to a given N degrees of freedom (for N = 1..6) ? I know for N=6 I can get a least-squares solution via ...
0
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1answer
706 views

Problem with angle calculation

I'm using MPU6050(accelerometer+gyro) connected to ATmega328P microcontroller, but probably it isn't even important in my case. In my project, I need an angle around the X axis. And it's calculated ...
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2answers
158 views

Dealing with fixed transformations while solving inverse kinematics

I am trying to solve inverse kinematics (using the Jacobian pseudoinverse method) for a 7 DoF arm, but because of the way the robot is mounted, the base frame does not coincide with the frame of the ...
3
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2answers
2k views

What is the torque/force required to rotate the base of a robot arm?

Take a look at the following simple example robot arm: I want to know the torque required on that bottom motor to rotate the arm. Since it's not exactly rotating directly against gravity like the ...
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1answer
367 views

How to construct rotary turn table (S/J1 axis) from ball bearing? [closed]

For my robotics arm project I have recently come across the following ball bearing at low discount price which I think could make a great rotary table for my arm. However it does not seem to have any ...
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2answers
3k views

Rotation matrix sign convention confusion.

In rotation matrix, Why do we rotate the first and third rotation in the opposite direction of the 2nd rotation, this is confusing. Image is attached with this. In this image we can note that for x ...
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5answers
983 views

Shield IMU from magnetic interferences

I experienced some drifting when coming near to magnetic fields with my IMU, so I wondered if it is possible to completely shield the IMU from external influences. Would this be theoretically possible ...
0
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1answer
123 views

Rotate 3d vector value into a single axis using a rotation quaternion

I want to rotate the whole value of a 3d vector into one axis using quaternion rotations. The reason behind is that I want to align the X and Y Axis of my smartphone with the X and Y Axis of my ...
5
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3answers
1k views

Generate transformation matrices for rotating around a object?

How do i compute all transformation matrices which places a robot endeffector at the shell of this sphere, with the end effector pointing toward the object in the center. I know at all time how far ...
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3answers
937 views

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 ...
0
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1answer
195 views

Hand-eye calibration?

I am having an issue with some hand-eye calibration. So i am using a simple robot which at its tool point has an stereo camera mounted on it. I want to perform some visual serving/tracking based ...
2
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2answers
589 views

Mechanical odometer with digital output

I would like to mechanically measure the distance a kids electric ATV traveled. The ATV will not be used with kids but as a mobile robot instead. It has a common rear axle for both rear wheels which I ...