# Tag Info

### Position Control vs Velocity Control vs Torque Control

I'm going to take a slightly different tack to Chuck. What is Torque Control? For me, Torque Control is about performing a move with an explicitly defined torque, rather considering torque just the ...
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### Position Control vs Velocity Control vs Torque Control

Torque is analogous to force for rotating systems, in that: $$F = m a \\ \tau = I \alpha \\$$ Where $\alpha$ is angular acceleration and $I$ is moment of inertia. $m$ and $a$ are mass and linear ...
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### Control VS artificial intelligence?

In robotics, it all boils down to making the hardware(in essence, the actuator) perform the desired action. The basics of control systems tell us that the transfer function decides the relationship ...
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### How to create a Industrial Robotic arm controller?

Industrial robots (e.g. Kuka, ABB, Fanuc) use a control cabinet which has the following main components: Drive amplifiers (controllers): The drive amplifiers are responsible for the closed loop ...
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### Impedance Control vs Position Control

In classical position control, the feedback controller only cares about the position error and is tuned to minimize it. This is done by using very high gains, i.e. if there is even a small position ...
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### What is the terminology used to describe control without measurement?

In control theory, we refer to this as "open-loop control", which emphasizes the lack of a feedback loop. The wikipedia article has several examples of open-loop control.
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### How to tune the PID parameters using Fuzzy Logic?

The paper Controlling of Quadrotor UAV Using a Fuzzy System for Tuning the PID Gains in Hovering Mode by E. Abbasi, M. J. Mahjoob explains how to tune PID gains with fuzzy logic. You can find many ...
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### How do I determine the required encoder resolution for a control system?

First I would question your math that got you to the 12b sensor. If you have a $dy$ of 1 mm over an arm that is $r = 1$ m long, then $\sin(\theta) = dy/r \rightarrow \theta = \mbox{asin}(dy/r)$. If ...
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### How to approach any advanced control problem in robotics

Models. If you want to get good at control engineering, get good at modeling. If you want to impress a controls professor, get good at modeling. Models are how you're going to do 90 percent of your ...
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### Can a state matrix have a row of zeros?

Yes, a state matrix with zero rows and/or columns makes sense and is viable. It typically signify pure integrators in the system. In the example you give,  \dot{v} = -\frac{b}{m} v +\frac{1}{m} u ...
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### Motion Planning vs. Control

There is a saying in software engineering which states that your company structure is reflected in your software architecture (I cannot recall the exact phrase). This is true for a robot control ...
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### Cartesian Velocity Control between Two 3D Poses

You essentially want to find the time derivative of a linear interpolation between two rotations. The easiest way to obtain this would probably to convert the rotation matrix between the two ...
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### Explanation of Quadcopter Dynamics, Components and Control

A couple things, the first is that the controller does not really care what the "real" values are. Everything is relative, if the controller sees that it is sinking it will increase the thrust until ...
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### PID control: zero out integral on error sign change?

Generally, in a well-tuned PID, most of the job is done by the P term, which is responsible for driving PV to SP. Then, D and I serve as corrections: the D term regulates the profile as of how we ...
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### Control VS artificial intelligence?

I think, it is easier to explain these areas in terms of guidance, navigation and control layers for an autonomous robot. Let's stay an autonomous robot is commanded to reach a desired goal position ...
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### How can I apply different control approach without having a state space model?

Many control strategegies (PID is not neceserily one of these) are computing some of their parameters from your system. If you do not want to model your system yourself (or play around with it until ...
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### Extended Kalman Filter in robotics - Worth it?

The Kalman filter is an optimal linear filter in the presence of Gaussian noise. It is optimal in the sense that it minimizes the mean-squared error. This means that the covariance of the estimated ...
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### PID and Kalman filters

There isn't really a relationship between them, unless you're asking how the dynamics feed each other when combined into a system. If that's the case, then I would suggest maybe starting with a ...
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### What is a Velocity Smoother?

The velocity smoother part of the code is this: ...
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### How to further understand the computed torque model controller

One of the most common controllers is a computed-torque controller, also known as the inverse dynamics. The preceding controller is based on the feedback linearization principle which is an approach ...
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### Why is it so hard to walk?

I'm not sure I agree that bipedal walking is so much harder that airplane control. It depends on how you look at it. Many robots can walk (bipedal walking) and many airplanes are difficult to control ...
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### How has the Mars Exploration Rover (MER) has been working for 11 years if it was designed for 90 Sol?

There are 2 main reasons why the MER is still operating long after it's 90 Sol planned lifetime. The first is political, strategic, and can be summarized as 'Under promise, over deliver'. When a PI (...
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### Why to combine a Raspberry Pi (or similar board computer) and an Arduino for controlling motors?

The reason is Clock on the Raspberry Pi. Note that the raspberry is powerful but not that powerful that it can run an OS and simultaneously give you precisely timed PWM outputs. I assume that you'll ...
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### State Space model for bouncing ball

Matrix notation in general is nice because of how compactly you're able to write and especially read everything, similar to using descriptive variable names in programming or performing algebra with ...
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