9 votes

Camera selection for long range stereo vision system (up to 100 meters)

I still think this is off-topic, but it seems I need more space than a comment to show (answer?) why that is so. You are starting from some performance specifications and are looking to get to a set ...
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  • 14.7k
5 votes

Is ROS hard real time safe?

ROS is not a real-time operating system. The purpose of ROS was not to be like VXWorx (which is what the Mars Curiosity rover uses). ROS was developed to be a simple, generic, reusable platform for ...
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5 votes

Raspberry Pi for two wheel robot?

A Raspberry Pi should be sufficient for the control you intend to do with it. In designing a controller under a full multitasking operating system, like the Linux operating systems that are available ...
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4 votes

When is the case to use hard real time?

In general, hard real-time OSes are used when there is a (usually periodic) task that is terminally critical, i.e. a process that needs to be run every few milliseconds, for example, and which, when ...
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  • 191
4 votes

What is the best adaptive controller for robotic arms?

The given strategies can be divided into two groups: model-based and model-free control. The AMPC and MARC suggestions are model-based the other are model-free. Theoretically, a pid controller can be ...
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4 votes
Accepted

Why does ROS2 claim to be "real time"?

"Realtime" is a fairly vague term. What ROS is referring to is often termed "soft realtime" because it is able to calculate control actions as fast enough to keep up with the robot'...
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  • 2,679
3 votes

Camera selection for long range stereo vision system (up to 100 meters)

I'll try to explain this in terms of software. Firstly, it is just next to impossible to have 100 metres (practically, 3 metres is like the best depth accuracy) and we need to be sure that the cameras ...
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3 votes

Software real-time of ROS system

You can use Orocos RTT with ROS to achieve some real time performance. In order to use this you need to patch the Linux kernel with a real time patch like PREEMPT_RT or run a real time kernel like ...
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2 votes

Real-time camera localisation in known environment

The problem you want to solve is definitely a SLAM problem and not just simply localization (or maybe we can consider it SLAm since the mapping part is not as heavy). The reason for this is that you ...
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  • 1,357
2 votes

Real-time camera localisation in known environment

As a matter of fact, if the environment is known a priori, then you don't need SLAM. It is a matter of localization problem which is simpler than SLAM in the sense that the map is given, therefore you ...
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  • 2,347
2 votes
Accepted

PID Integration over not constant dt (∆time)

Short answer: yes, as long as you adjust for the real dt you are fine Longer answer: In reality, we are always using discrete time approximations of continuous time concepts of derivative and ...
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  • 2,679
2 votes
Accepted

Path of the robot

One of the ways to do path tracking is by indoor mapping. In indoor mapping you can use Triangulation method. Basically, this method uses the help of Relative Received Signal Strength (RSSI) from ...
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  • 179
2 votes
Accepted

Quadcopter PID Tuning for Altitude Hold/Position Hold along Z axis

Currently I am performing my research on that, and in my case I decided to tune all the PIDs. Angles of the quadrotor tend to zero, while altitude controller tend to the objective height. That's ...
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  • 440
2 votes
Accepted

hard realtime signal processing

This sounds like a great project. You should have a list of at least 20 processors from at least 10 companies that you are choosing from when starting a new project. Understand your requirements and ...
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  • 4,225
2 votes

How can I measure latency in a CAN bus?

Use an oscilloscope. Place oscilloscope probes on an i/o line on the master and a motor phase line on the slave. Toggle the i/o line just before sending the can bus command for a step change in the ...
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  • 4,225
2 votes

Real Time Motion Control

The key elements to real-time motor control is the motor controller and the motion controller (which can be a CNC, a robot controller or other type of controller). The following description fits most ...
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  • 6,412
1 vote

PID control loop and feedback acquisition synchronization

This kind of control situation in general Nyquist method is used, In your first if your sampling period is 4 ms, your sampling frequency is 250 Hz, so you can control event maximum 125 ...
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1 vote

Head movement using gyroscope

You would have to integrate the rotational kinematics equations forward in time with a known initial orientation, such as R(0) = eye(3,3) -- identity matrix. You will have drift issues if you go out ...
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  • 11
1 vote

The reason(s)/benefit(s) to use realtime operating system instead of while-loop on MCU

Using an RTOS on a microcontroller is for reducing the complexity of developing your solution, and reduces the need for programmer expertise for device drivers, at cost of increasing the complexity of ...
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  • 4,225
1 vote
Accepted

controlling industrial servo with pc

Real-time control protocols for drive amplifiers are Ethernet based, but not necessarily compatible with your average Network card. You can take a look at the following protocols and decide which is ...
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  • 6,412
1 vote

Real time implementation of EtherCAT master with ros_control

You would confuse or mislead people if you called a non-realtime system with realtime subsystems a realtime system. If your motor control is realtime, just say that. That you have realtime control of ...
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  • 4,225
1 vote

Path of the robot

Since you have servo motors, you can record a sequence of motor rotations when you teach the path, then have the robot repeat these saved values as an array of destinations when you repeat the path. ...
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  • 4,326
1 vote

Path of the robot

I would recommend rotary encoded motor mostly used to track no of rotation(steps) used in roomba vacuum cleaner to record steps and compute if needed
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  • 41
1 vote

When is the case to use hard real time?

You should find it useful to read this https://www.researchgate.net/project/A-Preview-of-Introduction-to-Fundamental-Principles-of-Dynamic-Real-Time-Systems. "Hard" real-time is a special case of the ...
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1 vote
Accepted

How to eliminate motion blur with realtime performance

You don't need more frames per second, you need a shorter exposure time.
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  • 1,825
1 vote
Accepted

Is it possible to use an arduino in hard real time

The short answer is no, you will not be able to create a distributed system that meets the criteria of 'hard real time' using the approach you describe. The more nuanced answer is: It is ...
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  • 4,225
1 vote

Is it possible to use an arduino in hard real time

There are multiple different parts to your question. Can an Ardiuno be used "in in real-time"? Yes it can, it has hw timer interrupts, the tolerance of your oscillator will give the precision of the ...
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  • 6,412
1 vote

How to get live audio from robot?

Look into soundwireserver. Its an easy way to setup an audio server on a Linux or windows based system, and can be monitored from a laptop or an android phone. You need to consider processing ...
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1 vote

How does one calculate distance and angle using a target with known measurements?

I would suggest model based pose estimation. DeMenthon and Davies describes a method for finding the pose of an object using 25 lines of Code!
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1 vote

Real time operating system for robotics vision

Whether you actually require a realtime system is unclear. The only component for which realtime would be relevant is the computer vision application, and it sounds like you haven't written it yet -- ...
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  • 10.8k

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