10
votes
Optimal location of the center of mass for an inverted pendulum
The two views are not contradictory; they apply to two different situations, which you are treating as a single one.
Your personal experience about having a low center of mass applies to situations ...
- 11k
7
votes
Accepted
Finding Center of Mass for Humanoid Robot
Yes. As @hauptmech mentioned, you can use your forward kinematics to get the center of mass of each link in the base frame. Then you can simply compute the weighted average of the masses and ...
Ben♦
- 5,780
5
votes
Alternatives to Kalmam Filter
A good choice for sensor fusion with the MPU6050 is a second order complementary filter, which I used for the orientation estimation in a project. The complementary filter is computational cheap and ...
- 171
4
votes
Balance Bot PID tuning
Just a hint from my extensive experience from self balancing robots:
The most important aspect of a self balancing robot, is the actuator acceleration (torque) control.
(...) the motors start ...
- 71
4
votes
Should I use an arduino to control my balancing robot's motors?
If you want to have a good balancing, PID loop timing is very important. Standard Raspberry OS, like Raspbian can't guarantee you any precise timing, so once your loop period may be 10ms, once it can ...
- 963
4
votes
Accepted
Can I model a 1D segway as a cart-pole system?
Let's start by defining some of the quantities in the equations you gave:
$I$ Inertia of the pendulum about its center of gravity
$M$ Mass of the cart
$m$ Mass of the pendulum
$l$ Distance between ...
- 201
3
votes
Where should I put the angle sensor on my cart-pole robot?
The gyroscope placement shouldn't make any difference since the rotation rate will be the same everywhere (assuming your robot is rigid enough).
The accelerometer will pick up the rigid body ...
- 1,377
3
votes
How Should I tie My quadcopter to some thing, to adjust pid on one axis
Since you're trying to adjust the stability, you should make sure that your method of restraint isn't restricting the motion along that axis.
So, the preferred way to restrain a quadcopter is by ...
- 11k
2
votes
What PID values should I keep?
I asked for your code because I've found people tend to implement PID controllers incorrectly. It doesn't really matter what your gains are, if you're not calculating the error terms correctly and/or ...
- 15.9k
2
votes
Optimal location of the center of mass for an inverted pendulum
Lower centers of mass are more stable, but an inverted pendulum is inherently unstable; any perturbation will set it off.
The height to center of mass depends on how much track you have available, ...
- 15.9k
2
votes
Loop time for self balancing robot
The answer is not a trivial one. Because,
the system dynamics depends on multiple sub-system dynamics (including software, sensors, and actuators (motors in this case))
finding the optimum value for ...
- 411
2
votes
Accepted
How to maintain a robot's center of gravity
There are basically two approaches to this problem: You can solve it mechanically or through sensors/programming, or some combination of both.
jsotola's response offers several good mechanical ...
- 154
2
votes
How to maintain a robot's center of gravity
Use a couterweight.
It could be a second arm, or a pendulum inside the robot body, or even two partially filled water resevoirs with a bi-directional pump in between.
You could also clamp onto the ...
- 444
2
votes
Balancing robot - How to control the velocity and angle
First of all, well done on getting your robot to balance! If you’ve got this far the rest should be easy.
A cascading PI loop (no D) works very well for this. You have an outer loop to control the ...
- 21
2
votes
Alternatives to Kalmam Filter
Particle filters (epecially in Monte Carlo localization) always seemed easy to intuitively understand to me. You basically simulate bunch of possible states of your robot, rank them with probabilities ...
- 729
2
votes
Accepted
How to balance a humanoid robot on one feet?
Humanoid robots balance and motion planning are not trivial tasks. I believe you will learn a lot if you read about Zero Moment Point (ZMP). Basically, it is a specific point of contact between the ...
- 36
2
votes
Finding center of mass and support polygon for quadruped robot
I intend to find the center of mass of a quadruped robot and find the
convex of the CoM inside the support polygon. I want to make a model
of this, which is further going to help me develop stable ...
- 54
1
vote
How to balance a long vertical bar
I believe your intuition about using push-pull linear actuators is in the right direction: you would have a quite hard time to control such a structure.
Traditionally, to deal with a cart-pole system ...
- 3,985
1
vote
Accepted
Accelerometers in a self-balancing robot, can't we do better?
If you properly construct a Kalman filter with an 'x' input, then yes, it'll be better. Notably, the inertial sensor cannot give you an absolute value for x in any case, because you're (essentially) ...
- 1,891
1
vote
Accelerometers in a self-balancing robot, can't we do better?
While this isn't a complete answer to your question, I want to leave some of my thoughts. I think you missed:
Gravity itself, which points downward and is typically about 9.81 m/s² but might be ...
- 291
1
vote
Accepted
Two-wheeled self-balancing robot - Choosing the control system
You only have to do simple calculations.
We have done it with different hardware: first with a Lego mindstorm to prototype and then with a powerfull myRIO.
The hardware used:
Prototype: Balancing ...
- 26
1
vote
Balancing robot tuning approach
Well assuming you are using a filter(Kalman or Complementary) for the IMU, the PID tuning can be quite a cumbersome task. There is not a fixed end approach on tuning your PID. It took my Self-...
1
vote
How can I compensate for pendulum and cart motion when using an accelerometer to detect the tilt angle?
If an accelerometer is mounted along the pole axis of a pole-cart system with its axes oriented tangential and normal to the pole rotation, the components of acceleration can be found using rigid body ...
- 136
1
vote
Accepted
Why do I need an additional moment of inertia term in the cart-pole dynamics equation?
Look up an explanation of the parallel axis theorem for the mass moment of inertia. The two terms do represent similar things, but the axis of rotation is different. The term $I \ddot\theta$ comes ...
- 4,376
1
vote
Alternatives to Kalmam Filter
Want to get orientations from accelerometers and gyroscopes?
Use the Madgwick filter.
From the paper, "Results indicate the filter achieves levels of accuracy exceeding that of the Kalman-based ...
- 15.9k
1
vote
Alternatives to Kalmam Filter
Check this website pratical approach to kalman filter it will give you a comprehensive description of kalman filter for a balancing robot (like yours) both theoritical and pratical (you have the code ...
- 121
1
vote
Optimal location of the center of mass for an inverted pendulum
Since your control input to the system acts only on the cart, then you can influence the pendulum angle only due to the coupling between the cart motion and the pendulum motion. If you were to put ...
- 201
1
vote
Optimal location of the center of mass for an inverted pendulum
You can answer this by considering the equations of motion of an inverted pendulum: $$\ddot{\Theta} = \frac{g}{l} \sin(\Theta)$$
If you agree that the easiest system to control is that which has the ...
- 4,376
1
vote
What can this picture/data tell?
The natural frequency of your system is obvious from your graph. From that you can get a relationship between mass and stiffness (using a second order model). If you look at the growth in amplitude ...
- 4,376
1
vote
What factors should i consider when selecting a motor for a free wheeled cart-pole balancing robot?
High acceleration from a static (balanced) configuration is only related to high torque. However, the maximum torque you can deliver decreases as function of speed. So, in the end it depends on both. ...
- 562
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