Questions tagged [motion]
the action or process of moving or of changing place or position
85
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Calculate position of differential drive robot
How do you calculate or update the position of a differential drive robot with incremental sensors?
There is one incremental sensor attatched to each of the two differential wheels. Both sensors ...
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6
answers
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How to convert vertical motion to horizontal?
I am interested in using this miniature motor Squiggle Micro Motor to create very tiny horizontal movements. However, due to very limited space, I can only place it vertically within my project.
...
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2
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Can I use digital animation software to define the movements of humanoid robots?
I'm working with a lifesize (~130cm) humanoid robot (Hubo+) and looking for a way to easily program new motions and gestures into him. Obviously, I could write my own tool, but I am looking for a ...
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1
answer
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Cable routing in theta, x, y motion control system. Better inside or outside?
I'm building a motion control platform with 3 DoF: 1 axis of rotation (theta) and 2 cartesian (x,y). In most applications, like wrist actuation, you have an X-Y stage with a rotating servo as the ...
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2
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Instantaneous Center of Rotation for a differential Drive Robot
I want to find the instantaneous center of rotation of a differential drive robot.
Assuming I know that the robot will travel with a particular linear and angular velocity $(v,w)$ I can use the ...
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3
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What does SE mean in robotics literature?
I've come across the abbreviation SE several times recently. I know it has to do with the pose of the robot, and the degrees of freedom. Most recently I found it on page 8 of this paper:
D. Kragic ...
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3
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Motion Model for Holonomic Robot
We are working with an holonomic robot equipped with three (120 degree shifted) omnidirectional wheels. The relative movement is estimated by dead reckoning using wheel encoders. To improve this ...
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What are some good cheap, silent, motors for mannequin robots and what kind of controller should I use? [closed]
What are some good cheap, silent, motors for mannequin robots and what kind of controller should I use?
I'm creating mannequin robots that require 24 motors: 2 neck, 4 shoulder, 2 elbow, 4 wrist, 2 ...
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1
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Calculating Required Torque
Say I had an object with 4 motors/wheels attached (in a fairly standard arrangement).
I need to calculate the amount of torque required from the motors to be able to move the object of x kilograms ...
4
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3
answers
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Is there any advantage to velocity motion models over odometry motion models for SLAM?
I've seen several examples of SLAM algorithms (EKF SLAM, Graph SLAM, SEIF SLAM) written in terms of the velocity motion model. I have yet to see an example of any SLAM algorithm utilizing the ...
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Motion planning from a given path
Many articles reference algorithms such as A*, PRM or RRT based planners to motion planning algorithms which seems unreasonable since it is still necessary to parametrize found path with time.I wonder,...
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How do I adjust objects on a conveyor belt into the proper orientation?
This is part two of my larger robot, it follows up what happens with the small rocks here: What kind of sensor do i need for knowing that something is placed at a position?
Now i am taking the rocks ...
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1
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Velocity Model Motion in Matlab (Probabilistic Robotics)
I want to implement the velocity motion model in Matlab. According to Probabilistic Robotics page 124, the model is as following
\begin{align*}
\hat{v} &= v + sample(\alpha_{1} v^{2} + \...
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2
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State estimation of mobile robot
For a mobile robot - four wheels, front wheel steering - I use the following (bicycle) prediction model to estimate its state based on accurate radar measurements only. No odometry or any other input ...
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2
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Compensation for IMU mounting misalignment
I have an MPU6050 IMU and I would like to mount it on an FSAE car and use it to measure the yaw, pitch, roll, and angular velocities as it drives. As it's impossible to mount it perfectly flat and ...
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votes
2
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Motion planning and robot controlling
I am stuck with understanding how can I make my robot move along planned path. For instance, if we have a grid map of an environment and applied, for example, A* to plan a path then after that we have ...
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1
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Does a vehicle with defferential gear still move straight?
I am in the concept phase of a driving robot. The two wheels on the front axle will be powered, while the rear will be dragged along. The rear is also responsible for steering but this has noting to ...
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3
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Using robotic simulator for prediction step in probabilistic localization approaches
Probabilistic localization approaches like Kalman or Monte Carlo benefit from an accurate prediction step. The more accurate the prediction step, the more accurate is the belief of the robots pose. In ...
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votes
1
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What do we call a coupling with infinite range of rotation
In most situations, range of motion is limited by the fact that we need to carry power or information past a joint. So, past a certain point there are either cables in the way, or the cables would ...
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votes
1
answer
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Linear slider motor mount location - Pros/cons
I'm currently designing a linear camera slider, that will be used to hold camera equipment weighing just about 15 Kgs including all of the lenses and monitors and everything else.
For those who don't ...
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votes
1
answer
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SEIF ,online version of Graph slam create doubt in Motion Update state
I have a thesis work about Graph Slam The GraphSLAM
Algorithm with Applications to Large-Scale Mapping of Urban Structures
I try to implement it with the help of this paper but during the ...
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2
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What are the equations of a s-curve position path?
I have a decoupled mechatronic system with two motors. I want for each motor to give a s-curve path as reference. You can see in the image below the position path, velocity and acceleration.
All ...
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2
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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 ...
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Help with PID "units" in a quadcopter control system
I'm in the process of writing my own simple quadcopter controller for experimental use, and I'm having trouble getting my head around how to convert from the degrees which my PID controller demands to ...
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1
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Omnidirectional Movement for 3 Wheeled Spherical Omni wheel robot
I was watching James Bruton's video on his spherical omniwheeled robot and he was explaining how to go directly sideways. He explains this from 6:09 to 7:06. I didn't understand how the velocity of ...
2
votes
1
answer
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Why don't bipedal robots ever feature natural movement?
I'm a programmer and I've decided to make some bots for fun. I might start with wheels but my ultimate goal is to make bipedal robots. To that end I first decided to watch a bunch of videos of such ...
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2
votes
1
answer
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Equations of motion with mass attached to end effector and external force
I have to find the equations of motion for the given manipulator:
The links of the manipulator are considered weightless and the equations of motion have to be derived by using the Lagrange equations....
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2
votes
3
answers
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A powerful pull/rotate device that provides a certain (controllable) force?
I don't know how to call the device I'm looking for (or need to create), maybe you can help me with terminology too so I can at least search..
I want something that either rotates or pulls with a ...
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2
votes
2
answers
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How to relate forward kinematics into PWM/speed?
I am having a hard time understanding how to relate forward kinematics to things one can control in a robot like PWM and reading encoder values.
For example, how to relate the encoder values from ...
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2
answers
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Nano sized electric motors
What is a good website for buying 1.5V continuous motors? I'm looking to build a clockwork robot but I cannot find a motor small enough to fit inside my power box and I don't want to mount it outside ...
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2
votes
1
answer
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In Dynamic Motion Primitives, why we need to approximate f if f_target is given?
I seem to misunderstand something crucial regarding finding the force vector in the process of DMPs:
The way I understand it, I should come up with a dataset of trajectories $\{y_i\}_{i=1}^n$, and ...
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2
votes
2
answers
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Ackermann Motion Model Does not Drive in an Arc, but Turns on the Spot
Im trying to implement an ackermann motion model which estimates the x,y and theta for a robot I have.
I have a gazebo simulation running which publishes a steering angle for the virtual tricycle ...
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2
votes
1
answer
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Help with adaptive fill algorithm for Water Color Painting Robot
TL;DR:
Can anyone point me to a good adaptive path fill algorithm?
Hey there, my name is James, and my daughter built an awesome painting robot with her friends over at Evil Mad Scientist labs, even ...
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2
votes
0
answers
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Wheeled Mobile Robot State Estimation Model Using Odometry
I have a process model update that follows the form:
$$
\mathbf{x}_{k|k-1} = \mathbf{x}_{k-1|k-1} + \delta \mathbf{x}_k,
$$
where $\mathbf{x}_{k-1|k-1}$ is the posterior estimate from the last ...
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2
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0
answers
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Lost on SEIF Slam repeated update landmark
I am working on Sparse Extended Information Slam. I take the reference from Probabilistic Robotics, by Dr.Sebastian Thrun (Chapter 12,page 303). I have some doubt about the implementation of the ...
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4
answers
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How to turn a rover 90 degrees using wheel encoders?
I have a four wheel DC rover with two optical wheel encoders. I'm executing rover turns by controlling the direction of wheel motion on either side of the rover. To turn left, all wheels on the left ...
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1
answer
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Real Time Motion Control [closed]
How is real time control normally handled? Do you run a separate motor control unit which has its own RTOS or is there some other way?
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1
answer
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Probably basic question about how control a DC motor
over the past weeks I was trying to figure out how use the information from hall sensor to control a DC motor. Basically this is the motor which I'm using: https://www.servocity.com/32-rpm-hd-premium-...
1
vote
1
answer
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Quadrotor SE3 Controller: Calculating Rd_dot
I am trying to simulate and implement the controller in the paper Geometric Tracking Control of a Quadrotor UAV on SE(3). I have the dynamics implemented, however I am stuck at one part in the ...
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1
answer
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Best technique to built an ejectable drawer? [closed]
I want to build a closet with ejectable drawers. On the top should be 4 buttons, each eject opening one of the four drawers of the closet.
I am looking for ideas on how to accomplish this. What kind ...
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1
vote
1
answer
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Best way to generate a configuration space for a 6 DOF robot
I'm currently working on a motion planner for a 6 DOF robot but I can't figure of a good method to generate a configuration space.
The most basic way would be to test every position possible if there ...
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1
vote
1
answer
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Can ROS be an alternative for a KFLOP or RUMBA Board?
I have a few questions about controlling robot arm motion. I see that some have used Dynomotion KFLOP and other CNC motion controllers to control arms. Some have used Rumba board as well as several ...
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1
answer
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Can badly tuned Feedforward still decrease steady-state error?
Let's say we're trying to control the speed of a motor to 20 revs/sec, and we know that our controller output for that speed is approximately 5. We currently have a Proportional controller to drive ...
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vote
1
answer
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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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vote
1
answer
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Controlling YuMi robot by serial port
I'm trying to control the YuMi robot arm by a serial port. The serial port will give the information on what direction the end-effector should move and what is the velocity. What I would like to ...
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2
answers
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Estimating yaw angle and yaw rate for a frontal vehicle
I would like to know if it is possible (and if it is possible how can it be done) to estimate the yaw angle and yaw rate of a vehicle in front of me knowing the following information:
-my speed (x,y,...
1
vote
1
answer
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Step size in numerical differentiation
I get position information and a corresponding timestamp from a motion tracking system (for a rigid body) at 120 Hz. The position is in sub-millimeter precision, but I'm not too sure about the time ...
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1
vote
1
answer
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Square with hinge on all four sides
I want to make a component that will be a square plate that will behave like it has a motorized hinge on all four sides. That is, it can "open" by pivoting around any one of its four sides. I want it ...
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1
answer
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Glasses with eye sensors
Someone could tell me if there are wearable devices such as glasses, with sensors that can detect eye movement?
In particular, I would need a device like google glass, having a sensor or a camera ...
user9411
1
vote
0
answers
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Kinematic model of skid-steering mobile robot (4 wheeled mobile robot)
The kinematic model for skid-steering mobile robot (4 wheeled mobile robot) is
where state vector is $q = (x,y,\theta)$, and $\eta = (v,w)$ is the linear and angular velocity of the robot, and $x_{...
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