Questions tagged [control]
A method or device to manage, command or regulate some part of a system.
629
questions
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I can't use half the gpio pins and I can't use any pwm pins on the Nvidia Jetson AGX Xavier. What do I toggle to use them?
Most of the pins on the AGX Xavier are 'unused' gpio pins. Yet, only a few of the pins will actually work as gpio pins. I notice most of the pins on this diagram are labelled 1.8/3.3V. Some other gpio ...
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22 views
Dexterous Manipulation with Robotic Hand
I am currently working for my M.Sc. Thesis with the Allegro Hand with which I have to perform some simple in-hand manipulation tasks, such as lifting or rolling a cube with 2 or 3 fingers. This has to ...
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38 views
Simulate Wind in Gazebo - physics_msgs
I am trying to simulate a drone inside an environment with constant wind. I have found a good plugin (link below) and I have done the following to integrate this plugin in my system:
include the ...
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24 views
Differential Drive Control Techniques
I have a mobile robot that has a differential drive technique. I try to control the robot with PID controller. Is the best way for controlling differential drive robots?
If I want to compare different ...
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1answer
84 views
What is Wrong With My Stanley Controller for Car Steering Control
Hope everyone is doing well.
I am just trying out Microsoft Airsim for few days and few hours ago I wanted to implement a Path Tracking Algorithm for an Autonomous Car. For the lateral control, I ...
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1answer
27 views
Kinematic Bicycle Model theta units
I don't understand the $\theta$ units. The bicycle model defines $\theta$ as:
$$\theta=\theta +\frac{v\cdot\tan\delta}{L}\cdot$$
Where $v$ is the vehicle velocity, $L$ is the wheelbase distance, and $\...
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2answers
56 views
control of a rod attached to a motor
I have a 76 cm, aluminum rod, attached to the shaft of a 12v DC banebot motor. The rod is hanging vertically initially, and rotates in the vertical plane. The task is to control the rod to make it ...
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1answer
33 views
How to avoid oscillations caused by backlash in position control?
I am working with a ball screw mechanism driven by a brushless dc motor with an encoder mounted on the load side. We are using a PID position controller with tuning settings by optimization however ...
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1answer
24 views
Center line steering with differential drive
I’ve got 2 motors that drives my unit and I can easily steer it manually by simply adding more speed to one wheel vs the other.
Now I’m automating the rover using image processing to follow a driveway....
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19 views
Detailed resources for control of linear actuators including backlash/friction compansation and controller design?
I am working on a project where I would like to control a linear actuator with a ball screw mechanism. I feel I need a reference book for position/servo control systems for dc motors as there are many ...
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2answers
65 views
How to find the nonlinear equations of motion of a seesaw-cart electromechanical system?
So what I have here is a single pendulum with a cart system. The pendulum is composed of a set of rigidly connected parts integrated in a seesaw-like structure which can freely pivot around the axis ...
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1answer
37 views
Choose the structure of the dynamic model for the generalized equations of motion of the robot
I ask the robotics specialists for help as I am a little confused.
I have two subsystems which are shown in the picture below:
One of them is a system of stable and controlled differential equations ...
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0answers
24 views
The math behind minimum controller sample rate compared to actual error frequency spectrum
It seems intuitive to me that, in a digital system, a system sampling the error rate "too slowly" will fail to stabilize the system.
Is there a theory/set of metrics/equation I can use to ...
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2answers
116 views
How do I find the transfer function for my quadcopter altitude system?
This is not so much of a how but if I am right so far. I am looking at the z-axis now only. The linearized equation of motion for the thrust in the z-direction is:
$$
T=m\cdot \ddot{z}+mg,
$$
where $m$...
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57 views
Outer Position Loop to Control Inner Velocity Loop
I'm trying to control the position of a brushless DC gearmotor. To drive the motor, I have a controller box that provides a velocity that is proportional to a 0 to 5 V input. The motor has it's own ...
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14 views
What are common method for sensor feedback in teleoperated underwater ROV to close the control loop
I would like to know what are the common method to get sensor sensor feedback in teleoperated underwater ROV to close the control loop. I mean does it use Velocity or Force and what sensor are used. ...
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1answer
209 views
Self balancing bike using a flywheel: ROS implementation
I have a bike with two stands and a flywheel like this:
The stands can be adjusted so that they don't touch the ground. Now, the task is to implement a self balancing mechanism: when I run the script,...
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1answer
31 views
Discretization of a control module
The desired control is $u_f=\frac{1+\eta s}{1+hs}a$, where $u_f$ is the feedforward control, $a$ is the feedforward observation and $\eta$ and $h$ are two constant parameters. However, I can only ...
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2answers
62 views
Servo Starts Oscillating Under Disturbance
I'm using MG996R servos to control a 6-axis desktop robot arm. When no disturbance (like a gentle push to the robot), the servos are fine and can hold their places. But under a gentle disturbance, ...
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0answers
25 views
Obtain a State Space System given Denavit-Hartenberg parameters and a Rigid Body Tree model in MATLAB
I'm confused regarding the representatoin of a 6 D.O.F. robot arm with multiple links. I have the denavit-Hartenberg parameters and have used these to create a Rigid Body Tree model in MATLAB. The ...
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1answer
68 views
Implementing PID on a line following bot using turtlebot
I am using ROS melodic,turtlebot 2 on Ubuntu 18.04.
The idea is to create an environment consisting of lines as a path (slightly curved), and to program the turtlebot to follow the lines. Basically, a ...
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1answer
50 views
can anyone explain detailly this video(title: sensorless active complaince)
https://www.youtube.com/watch?v=g8Je93soOZE
i am interseted in how they achieve compilance and detect collision in servo without the use of sensors. so any one please explain briefly
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1answer
57 views
Mapping Joystick Inputs to Quadcopter
hope you are all doing well.
We are doing a project where a quadcopter is controlled by an ordinary joystick. We have constructed the Control Algorithm and the joystick to move the quadcopter in ...
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57 views
Is feedback control fundamentally efficient than open-loop control?
Is feedback control more efficient in principle than open-loop control? Is there a name for the principle? (I'd like to do an internet search to understand that theorem.)
Under ideal conditions, ...
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1answer
48 views
Identifying joints from transformation matrix (DH matrix)
Given a transformation matrix formed using the Denavit Hartenberg method, is there a way to identify joint paramters: for example the order of joints?
I've come across a solution to an exam question ...
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35 views
PI controller for skew angle on a train wagon like robot
I have a robot very similar to a train wagon, it has 4 actuated wheels controlled by 2 motors. The two wheels that are located on the same rail are controlled by the same motor.
On each wheel it's ...
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1answer
119 views
Can someone explain this yaw angle calculation equation?
Nowdays, I am trying to understand PX4 Autopilot(Drone Flight Control Open Source) attitude control code. But I can’t understand formula below which is in attitude control code description.
Can anyone ...
3
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1answer
67 views
Pose difference estimation in cartesian impedance control
I am trying to implement a cartesian impedance controller in simulation (gazebo + KDL). The method which I am using is the following:
Compute the EE pose from KDL's forward kinematics for the ...
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2answers
114 views
Equations of motion in matrix form and energy consumption
I am working on Lagrangian derived high-dimensional motion equations for a robot in matrix form. The structure of such an equation is known:
$M(q)\ddot{q}+C(q,\dot{q})\dot{q}+G(q)=0$
In here, $M(q)$, $...
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0answers
22 views
Navigation with obstacle avoidance without precise velocity measurement [closed]
I'm working on autonomous navigation and obstacle avoidance using a few small, education-purpose differential drive robots. The robot's motor can be programmatically controlled via PWM but the robot ...
3
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1answer
65 views
Visual servoing: simple control law
The problem
I have a control scheme like the one in the image attached below (Source: Robotics, Vision and Control Fundamental Algorithms In MATLAB®, Peter Corke). But instead of a robotic arm, I have ...
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1answer
79 views
Robot Operating System can be usable other than Robot application?
I am asking very general question, but i would appreciate if someone helps me. I want to use ROS for manufacturing process (Not robots) as a middleware that can create simulated Cyber physical system ...
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1answer
59 views
What is the terminology used to describe control without measurement?
I am currently writing a paper on information theory. In the paper, I will be comparing feedback control ( with observations of the environment, of course) and control without observations.
My ...
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3answers
64 views
Best way to control a robot from an application
I developed an application that places itself just before controlling the robot (CAD/CAM like application) and now I want to control my robot directly within the application.
Typically I have two ...
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39 views
Can the PCB Circuit Board be removed and replaced from inside the Create 2: Programmable Robot? [duplicate]
For a school project, the professor wanted to know if needed that the PCB Circuit Board could be removed.
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26 views
Data gathering and selling [closed]
a friend of mine is building various Robots with different structures, sensors, limbs executing different tasks. He gathers data from all sensors etc regarding technical and scientific range of ...
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3answers
109 views
Servos jittering problem
So I started building this 3D printed Bluetooth robotic arm that can be controlled via MIT app inventor from HowToMechatronics.com. After connecting all the servos and running the code, the servos ...
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2answers
122 views
Is there a way to send commands to the Staubli CS9 from remote system via TCP/IP??(like ur_rtde, urx libraries for UR robots)
I am new to ROS development and Staubli robots. Though i have some prior knowledge on UR5e, I am finding it hard to understand the architecture of Staubli and its other programming interfaces (like ...
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1answer
57 views
time varying gain LQR vs fixed gain LQR, in finite horizon and infinite Horizon
Consider the dynamic system
$\dot{x}=Ax+Bu$ and the optimal control formulation of
$J = x^TQx + u^TRu$, with optimal linear feedback $u=Kx$ where $K$ is the gain matrix, and I use $k$ to denote time ...
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1answer
61 views
How to design a PID controller for boat?
I have a boat with two trusters and a trajectory planner which is based on the bicycle model. In order to control the boat, the linear velocity of each truster has to be provided.
The following ...
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0answers
29 views
Multidimensional obstacle avoidance in ODE. Part II
Multidimensional obstacle avoidance
https://math.stackexchange.com/questions/4146255/multidimensional-obstacle-avoidance-in-ode
For some time, I studied this question more closely and came to the ...
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22 views
Optimization problem of the SPMs design
This article contains section 4. Optimization problem of the SPMs design
https://www.sciencedirect.com/science/article/abs/pii/S0921889014001250
Tell me please, are there any special programs for ...
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1answer
53 views
Multidimensional obstacle avoidance
Artificial potential barriers are known that allow robots to avoid obstacles. They are constructed as follows. https://authors.library.caltech.edu/106548/1/2010.09819.pdf
Can you please tell me how ...
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1answer
45 views
How can I achieve a square pulse train while sending pulses one pulse at a time to a stepper motor?
I am trying to control Stepper motors which has a pulse input driver.
I have a speed of 1000pps, and I want to move 1 pulse at a time. So that means 1 pulse will take 1ms.
After I send a command to ...
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22 views
Looking for a course (online?) RE: systems with XY stages
Using XY stages is common in many fields:
3D printing
Genetics instruments
semiconductor lithography
automated microscope slide imaging
See for example https://www.asml.com/en/technology/lithography-...
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17 views
Fuzzy Path Planning for an Unknown Environment
I have a problem to programming on Matlab the path planning fuzzy in an unknown environment I am using a fuzzy toolbox for fuzzy rule
How to do obstacle avoid by Matlab demo program
How to reach the ...
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1answer
65 views
Robots Following Robots with Safety Distance Planning and Coordination
I have two robots, I wish for the second robot to follow the first one while keeping a constant distance d_safe between them. I am trying to implement a PID ...
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0answers
19 views
MAVLink data stream to third-party system
I'm a completely beginner with pixhawk and MAVLink. So I want MAVLink (via AP Mission Planner) to send vehicle data e.g. attitude etc. in real-time to a third-party system that has a built-in ...
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65 views
How to perform a cart-pole swing up task using MPC?
I originally thought this was a really simple problem. However, to my surprise I did not find any resource talking about it, the only thing I found was that using Matlab's nonlinear MPC toolbox you ...
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48 views
Find viscous friction for DC motor transfer function
How do I find the viscous friction for my DC motor without measuring the input current and output torque.
I have to do a theoretical model on simulink and can't find any answers on how to find it
