13
votes
What's the difference between a holonomic and a nonholonomic system?
For a nonholonomic system, you can at best determine a differential relationship between state and inputs. You cannot determine a closed-form geometric relationship. This means that the history of ...
- 4,326
7
votes
Accepted
What does SE mean in robotics literature?
In that context, SE means "Special Euclidean" group, e.g. SE(3)* which is shorthand for "the special Euclidean group of rigid body displacements in three-dimensions".
*Planning ...
- 1,009
6
votes
What's the difference between a holonomic and a nonholonomic system?
A holonomic constraint is a constraint on configuration: it says there are places you cannot go. That is a reduction in freedoms. That’s (usually) bad.
A nonholonomic constraint is a constraint on ...
- 516
5
votes
How to convert vertical motion to horizontal?
Scott-Russell type mechanism. For weeks I was trying to come up with a solution for that exact problem for a engineering project mine. Look it up.
- 61
4
votes
Accepted
Are robot's codes usually compiled or interpreted?
Robots tend to be portable devices powered by batteries. Portable battery operated devices tend to use embedded processors with limited power and memory. Compiled code has several advantages over ...
- 451
4
votes
Accepted
Math behind trajectory planning
Since the problem is one dimensional, you are actually asking to compute a velocity profile. (A velocity profile is the information of how a path is traversed with respect to time.) Now the problem is ...
- 1,799
4
votes
What does SE mean in robotics literature?
It is a mathematical concept call the "Special Euclidean" group. Roughly, it is a combination of a rotation and translation. You'll also frequently see SO3, which is the special orthogonal group which ...
- 2,679
3
votes
Accepted
Robot mechanism parts names
This is called a Stewart platform. You can use any linear actuator type, hydraulic, pneumatic or electric.
- 481
3
votes
What does SE mean in robotics literature?
$SE(3)$ is the representation for both translation and rotation in 3D space, whereas $SO(3)$ is only the representation for rotations. $\mathbb{R}^3$ is for translations in 3D space.
If you only ...
- 31
3
votes
What's the difference between a holonomic and a nonholonomic system?
Holonomic constraints are constraints that can be expressed in the form of an equation relating the coordinate of the system and time
Non-holonomic are constraints that cannot be expressed in the ...
- 31
2
votes
How to convert vertical motion to horizontal?
This should have probably been a comment to @RobertEnglish answer ... but comments don't seem to allow pictures
Bavel gears. Plastic ones should be rather inexpensive.
- 137
2
votes
Is this gear design feasible?
Hmm, thats definitely a unique idea. I think the shape of the top gear would have to be rounded off like half of a torus so it maintains a good interlocking through the motion from parallel to 90 ...
- 306
2
votes
Accepted
What are the different ways to control distance to be covered by a robot?
There are far too many to list them all here but I can list the most common ones:
As you said base the movement off the motor RPM, and the diameter of the wheels and move for a period of time. This ...
- 1,909
2
votes
Basic question about Markov Localization, probability and belief distribution shift
Here is what I 'believe'.
Lets make the diagram more labeled. Say door 1 starting from left most is at 4 meters from the origin at left, door 2 at 7 meters, door 3 at 15 meters.
When the robot senses ...
2
votes
Accepted
Basic question about Markov Localization, probability and belief distribution shift
The robot has sensed a door, so the initial belief distribution matches the three possible door positions. i.e. the only three places that it is possible for the robot to be in that scenario.
The ...
- 1,009
2
votes
Basic question about Markov Localization, probability and belief distribution shift
I think this is just a way of illustrating the main idea behind the probability distribution and the representation is not complete.
The idea is that there is a moment when the door is detected and ...
- 6,412
2
votes
Accepted
State estimation of mobile robot
My solution is to use the following model with disturbance only at acceleration and curvature.
$$
\begin{bmatrix}
x_{k+1} \\
y_{k+1} \\
\theta_{k+1} \\
v_{k+1} \\
a_{k+1}...
- 198
2
votes
Can I program my roomba to run essentially all day (except for charging, of course)?
If I understand you right, you want to achieve that three roombas clean 24 hours a day, just making a break if they need to recharge and then continue.
The Create 2 is a roomba robot that is similar ...
- 271
2
votes
Can somebody explain how these forward kinematics matrix equations were formulaed?
It looks (to me) like there's a typo in that answer. The approach is to recognize that you have to wind up at the same point, whether you get there via the left arm (d->e->blue dot) or the right arm (...
- 14.7k
2
votes
Accepted
how to implement trapezoidal velocity profile in code
Not sure how you're choosing to structure your code, but typically I'll have a master reference, in percent, and a rate limit, in percent per second. You can have different rates for acceleration or ...
- 14.7k
2
votes
Accepted
Conveyor Belt Calibration for a Robot - Rotation Matrix
A general approach would be to construct a so called axis-angle representation and convert that to a rotation matrix representation.
On order to do so, one could start with a normal vector of the ...
- 6,412
1
vote
How to move robotic arm in straight line
First of all you should start to check 2 things:
the angle $\alpha$ is given by some sensor
the object and the path to the object (blue dotted line)
both lie in the arm workspace
If 1. is not met, I ...
- 1,327
1
vote
Are robot's codes usually compiled or interpreted?
Many people use Python to control robots. While it does use more computing resources to interpret the python code, it may take less time for the programmer to develop in an interpreted language.
...
- 552
1
vote
Estimating state of moving object from other moving object
It sounds like you can estimate everything you need to with a direct calculation of the transform between each vehicle since that is provided for you. For the derivative parameters, if your sensors ...
- 4,225
1
vote
Robot Veering to the Left
There are 4 possibilities:
One of the wheels' centre is displaced slightly.
Wheel encoders are not properly positioned and this is causing issues (like wheel pausing at odd positions while ...
1
vote
Robot Veering to the Left
Lets suppose, that left wheel is blocked, so nMotorEncoder[LM] is constantly zero, while nMotorEncoder[RM] counts something. ...
- 443
1
vote
holonomic and non holonomic constraints in layman's term
A constraint on the $k$ coordinates $r_1,r_2,...,r_k$ is holonomic if it is an equality constraint of the form $$g(r_1,...,r_k)=0,$$ and nonholonomic otherwise. These sorts of constraints arise ...
- 916
1
vote
High-traction thin tires vs Wide moderate-traction tires? [Sumo-bot]
Well, I moved my answer here from the Engineering SE because it looks like your question is probably going to get closed there, just like it got closed at the physics site.
Assuming everything about ...
- 14.7k
1
vote
is it possible to track movement on a tennis court?
Well the IR tracking system can work, but I think you need to place the camera at the ceiling.
Usually the distance between player and camera at the ceiling of a tennis-hall (height 8+m I guess) stays ...
- 1,647
1
vote
Robot start-up movement problems
Try running the motors in free-load condition (holding in air). If motor runs then, most likely they are not able to carry the load or the battery is dying. Try replacing the battery & see if that ...
- 11
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