Robotics Stack Exchange
Robotics Stack Exchange

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1500 questions
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votes
1 answer

Optimal-time trajectory in 2D and 3D with simple constraints

I'm trying to find the optimal-time trajectory for an object (point mass) from point p0 with initial velocity v0 to point p1 with velocity v1. I'm considering a simple environment without any obstacles to move around. The only constraint is a…
nwellnhof
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Wheel odometry simulation using ground truth

I'm tracking the state of a robot $X=(x,y,\theta)$ where $x$ and $y$ are the ground coordinates and $\theta$ the heading angle. I have the ground truth states $X_{gt}=(x_{gt},y_{gt},\theta_{gt})$. I want to simulate the wheel odometry using the…
Daphnee
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Inverse kinematic orientation problem

I am trying IK for 5-DOF robot all revolute joint. I am working IK with Jacobian inverse i.e end effector velocity = J inverse * error vector. In error vector I am feeding (x,y,z) positional error; this gives me correct positioning by first 3 joints…
manan kalsariya
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From a linear force actuator that spans multiple links and joints to the equivalent motor torque

I am programming/using a rigid body joint-space dynamics solver for robots in which I want to implement linear force actuators between links with their equivalent torque sources that are 'spanned' by this linear actuator. Consider the example figure…
Retinite
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Robot Calibration using DH parameters

I'm new in robotics. My problem is the next one: I have a 6DOF robot manipulator and because the implementation was for real-time application my calculation time had to be really fast so that I used Wrist Center position(Geometrical solution). After…
Paul Tumbaco
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Why are joint velocities very high near a singularity?

I am reading about singularities and I know that those are configurations which result in the same end-effector position and orientation. I also read that joint velocities get very high near that singularity but I don't understand why. I get it that…
kassio
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Flight controller drift issue

(This is a little long) So I am working on a drone recently, and aim to control it using an Android device. I've read that it can be done using a Raspberry Pi and Multi Wii, but I couldn't find any crius multiwii boards for sale anywhere. So I…
user148898
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Expressing a global point in different frames

I am trying to express a vector defined in global coordinates in different frames using homogeneous transformation matrices. There are in total 3 frames. Frame 1 lies in the origin and is fixed to the world. Frame 2 is fixed to a floating body,…
jim
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2 answers

How do you arrange the dof in a robotic arm?

I'm designing an arm that can manipulate objects on a table. My question is about the arrangement of the degrees of freedom. Different robots seem do have different arrangements of the degrees of freedom,. e.g. the open-source thor robot uses…
Tarrare
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Using jacobian of arm robot to calculate transformation matrices?

I have been given a Jacobian for a 3 revolute joint robot. I need to obtain the origins of each of the joint. Origins of the joints can be obtained once I get $T^0_1$, $T^0_2$, $T^0_3$ and $T^0_4$. 4th frame is my end effector. Is there any way to…
therobotgeek
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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 space is the set of all possible configurations the…
harsh
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3
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OpenCV get topdown view of planar pattern by using intrinsic and extrinsic from cameraCalibrate

Originally I have a image with a perfect circle grid, denoted as A I add some lens distortion and perspective transformation to it, and it becomes B In camera calibration, A would be my destination image, and B would be my source image. Let's say…
ricecakebear
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1 answer

Self balancing roboter IMU issue

I build a self-balancing robot, at least that what i should have been. now i have tried implementing a complementary filter which combines gyro and accelerometer data, but the problem is that the motor and the IMU (MPU 6050) are on the same board…
Daniel D.
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3
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1 answer

Waterproofing LiDAR?

I am interested in using a cheap LiDAR module for an outdoor robot I am building. The LiDAR modules that I am looking at are not waterproof and I was wondering how hard it would be to build a waterproof case and how much that would impact…
user16549
3
votes
1 answer

Correct Quadcopter Yaw control implementation

I have built a quadcopter from scratch, including my own flight controller. I have implemented a sensor fusion algorithm (Madgwick algorithm), which returns me current Yaw, Pitch and Roll angles. Then, a PID control algorithm based on these…
O.W.Grant
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