# Questions tagged [orientation]

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### Does the Factored Quaternion Algorithm Account for Declination?

Looking at the documentation for the Factored Quaternion Algorithm (FQA). In section 2 they define NED as the traditional Earth's fixed coordinate system, thereby referring to 'true' north. However, ...
22 views

### Robot Localization pkg / Motion Model prediction step

As I was investigating the transition functions in the prediction step in the ROS Robot Localization pkg (ekf.cpp) . I found for the orientation equations there are as follows: Roll angle is the ...
1 vote
23 views

### how to adjust mobile robot orientation If an obstacle is detected within the minimum safety distance?

I do have calculated a trajectory for holonomic and omnidirectional mobile robot and make the robot follow the pre-defined trajectory making use of the resolved-velocity control. However, in some ...
59 views

### How to keep the orientation of end effector during movement in ROS Gazebo simulation

I am using Ubuntu 20.04, ROS NOETIC, Moveit to control a UR5 robotic arm in Gazebo simulation. I am trying to move a robot with a fixed orientation of its end-effector. The basic idea is to use the ...
1 vote
44 views

### BNO055 mounted orientation configuration

For this BNO055, I am trying to figure out the correct transpose and sign tuples (or the byte values) for reorienting the sensor ...
47 views

### How are these equivalent rotation coordinates related?

I am using a 6 DOF UR5 robotic arm. I am successfully sending it commands in the [X,Y,Z,RX,RY,RZ] format. When I read back these coordinates, I find that the X, Y, Z values are the same but the RX, RY,...
1 vote
29 views

### How to compute orientation error for a Puma end effector

i hope that you'll be ok! I'm trying to control a Puma robot using the inverse kinematics in Matlab. I used unit quaternions to express the orientation of End Effector frame and orientation of desired ...
1 vote
223 views

### GPS to Cartesian

I'm interested in turning GPS position into Cartesian, I want to then transform it so the starting point is the origin. Anyone have experience with this?
69 views

### 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 ...
277 views

### How to control end-effector orientation with vector part of quaternion?

I was reading this paper: Closed-Loop Manipulator Control Using Quaternion Feedback, and it mentioned that you could control the end-effector orientation using a resolved rate controller where the ...
41 views

### 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 ...
65 views

### Kalman filter problem with the output

i want to use kalman filter to estimate my phone position, the measurments data is at this point just the accelerometer and the sampling rate is 3ms, i used the library pykalman, i have also wrote my ...
283 views

### Analytical solution to inverse kinematics of 5 dof robot arm

the followings are the equations I worked out for the inverse kinematics of a 5 dofs robotic arm. First of all, the kinematic diagram: For the joint angles $q_{2}, q_{3}$ and $q_{4}$ I resorted to ...
221 views

### Why are Euler angles used for drones

I know this question is asked before, but the reason why was still not clear to me. If you've a 6-DOF IMU, the gyroscope measures is degrees/s or radian/s. Why do we want to convert the body rates to ...
1 vote
144 views

### Looking for benchmarks on Apriltag pose estimation

we want to know if we can use Apriltags in our project for pose estimation in rather long distances and on moving target. Specifically, correcting errors of an IMU device on an autonomous vehicle. I ...
1 vote
515 views

### Why does AHRS system with Madgwick filter has so big drift?

I have an MPU9250 on my PCB and I use an AHRS system with a Madgwick filter to get yaw angle. I want to get very accurate and non-drifting yaw angle, but, for unknown reasons, I can't. I calibrated ...
128 views

### C program to find the rotation matrix (orientation) of a 6DOF robot from its end effector position and link parameters

I'm writing a C program to find the inverse kinematics of a 6DOF robot. I've been able to write it successfully based on the general concept of Inverse Kinematics using DH parameters (i.e. finding the ...
1 vote
491 views

### Obtaining Heading vector from IMU

First time here. I'm an electronics engineer who has been tasked with this problem: Given the 4D quaternion representing a vehicle orientation, how do you get the heading vector? The vehicle ...
361 views

### Orientation Problem of a 4-DOF manipulator

As shown in figure, I have a 4-DOF manipulator. I want to control the robot such that the end-effector should always be pointing down no matter where the robot is in the end space. For the ...
142 views

### How can i consider orientation of 6dof manipulator for inverse kinematic?

i been trying to code IK solver for few days, and i finally move the robot to the desired position. However im having hard time to orient the end-effector as i want it. I read the "Robotics ...
1 vote
72 views

### Define end-effector quaternion orientation from unit vector

I want to define ee-poses from a point cloud in a way that the pose for each point is pointed to by a unit vector from origin. Rotation about the vector pointing towards the point can be whatever as ...
85 views

### Looking for resources regarding conveyor object allignment / object orientation

Im currently on the hunt for resources / examples / words to use in a search engine in regards to orienting (aligning, funneling) an object on a conveyor. I am looking for techniques / utilities used ...
1 vote
553 views

### GPS Course vs IMU Course

Im currently working with Kalman Filter for position and velocity, one of the important parameters that im using is the heading that the sensor fusion of the imu gives me, but i have seen that the GPS ...
90 views

### Problem with calculating relative orientation

I am using an IMU which provides absolute orientation of the sensors frame $S$ relative to an earth-fixed frame $N$ in quaternion form, $^S_Nq$. In my experiments, I first obtain an initial ...
72 views

### Finding orientation of object in 3D space

Given the above constellation, I have to find the orientation of object B in the coordinate system of Object C. The objects A and B are fixed to a certain place and the object C can move in freely in ...
1 vote
239 views

### How to estimate proper heading angle

I obtain the heading or yaw angle from a source which I am not allowed to modify, but when the angle goes more than +180 or -180, it interchanges either from 180 to -180 or the other way around. Any ...
425 views

### Forward Kinematics for Two Axis Gimbal Mount

I'm trying to work out the orientation of a block at the end of two axis gimbal. I know the position of the two rotational joints, but would like to calculate the final orientation of the block given ...
1 vote
76 views

### 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 ...
1 vote
256 views

### Compute orientation velocities 6-DOF robot

I am trying to compute the joint velocities a 6-DOF manipulator(a typical industrial robot). I have an initial position [xi, yi, zi, T1i, T2i, T3i] and goal position [xf, yf, zf, T1f, T2f, T3f] in the ...
1 vote
82 views

### Signed difference between two directions

I want to get the difference between the orientation of my robot and a target point. The orientation is expressed as an angle as shown in the pictue below. The point is expressed as ...
95 views

### Extract Euler angles from angular velocity profile

I Solved inverse velocity (joint velocity) at velocity level problem. So, I have actual orientation of the manipulator. Now I wanted to get the desired orientation from angular velocity that I used to ...
1 vote
106 views

### Does GY-271 (HMC5583L) or any 3-axis magnetometer suitable to detect orientation?

Based on the datasheet, HMC5583L has 160Hz output rate and produce three axis direction angle data, X, Y, and Z. It can measure diversion from Earth magnet field with 1° to 2° accuracy. Does that ...
41 views

### 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 ...
939 views

### How to compute the orientation error between two 3D coordinate frames?

For my master thesis in robotics I have to compute the orientation error between two coordinate frames, called E and H. Their orientation is expressed through rotation matrices (3x3) with respect to a ...
1 vote
43 views

### Determining Orientation of a Robot Relative to a Line on Table

I am currently busy with a robot that needs to obtain it's orientation relative to a line seen by a camera. At the moment, I am using Hough lines to obtain a gradient for the line, but the gradient ...
1 vote
108 views

### Problem defining rotation matrix

I am studying robotic kinematics , and given the following manipulator with its D-H frames assigned: I have to find the rotation matrix $R_{e}^{2}$, which is the rotation matrix of frame $e$ with ...
716 views

### 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) & -\...
1 vote
1k views

### Yaw, Pitch, Roll rate concepts and how to calculate them with an IMU

I need help understanding the difference from Y/P/R rate and the data that I can get from a gyroscope. I am using the raw readings of my IMU (MPU9250) and the Madwick Filter to calculate a quaternion ...
2k views

### In SLAM loop closure, What does a sim3 matrix do?

I am confused between 3D rigid affine(with scale, without shear) transformation and Lie group's sim(3) matrix. 3D affine would be [sR|t; 0 1]. we rotate, scale and then translate a 3D point using ...
957 views

### State of a Robot

I saw the expression "robot state" in many articles and resources, but I could not understand what that exactly mean. What does state of a robot exactly refers to ?
1 vote
297 views

### 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 = (...
23 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). ...
112 views

### What is an axial and polar vector?

In Robot Kinematics and Dynamics by Herman Bruyninckx, it states: Axial vectors have an inner orientation, i.e., the direction of the vector indicates the positive orientation. For example, a unit ...
48 views

### Sensor complement in Drone

I saw a question posted by @Rocketmagnet (Why do I need a Kalman filter?) about the need for a Kalman filter. In that question, he says he's designing an UAV and lists the following sensors he will ...
938 views

### Yaw drift when implementing AHRS filter fusion

I am using the Matlab AHRS filter fusion algorithm with an InvenSense ICM-20948 to determine object orientation. I seem to be obtaining reasonable results however I am getting what appears to be ...
1 vote
887 views

### Inverse kinematics with end effector orientation?

I'm trying to implement an inverse kinematics solver, but this time even with the end effector's orientation. I succeeded with the case when the end effector only requires the position. I learned ...
4k views

### Orientation from magnetometer data

I saw lot of topics with the same title but answers are different. I have a magnetometer in my phone which give me the components of magnetic field in direction of X, Y, Z. If my phone lays on a ...
85 views

### Fixing robot orientation using AR

I am creating a project where a robot needs to face a control panel and do some specific tasks. Some reference tags will be placed on the panel. I want to use the tags as AR reference and fix my ...