Questions tagged [control]

A method or device to manage, command or regulate some part of a system.

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Balance 2-wheels robot without making it drift forward/backward

I'm trying to design a controller to balance a 2-wheels robot (around 13kg) and making it robust against external forces (e.g. if someone kicks it, it should not fall and not drift indefinitely ...
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What is the meaning of joint space and configuration space and task space?

I'm reading an article about teleoperation systems and it talks about three spaces that include joint space, configuration space and task space frames. I do not know what these are, can you explain?
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Kalman filter problem with the output

i want to use kalman filter to estimate my phone position, the measurments data is at this point just the accelerometer and the sampling rate is 3ms, i used the library pykalman, i have also wrote my ...
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Superposition in state space equation with multiple harmonics in the inputs

I have a question related to the superposition in state space equation. Suppose I have a state space equation below \begin{equation} \frac{d}{dt}X = AX + B\begin{vmatrix} u_1(t)\\ u_2(t) \\ \end{...
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why it is a dissipating term and is the second order?

corresponding paper why it said that $-\lambda \frac{|\dot{x}|\dot{x}}{2}$ is a small second order dissipating term ? For a linear second order system, the velocity is a dissipating term, because I ...
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how the two equatoin are linearized

corresponding paper Question1: how the equatoin 3 is linearized in the neighborhood of the equilibrium point $x = x_{sp}, \dot x =0 $ Question2: how the equatoin 12 is linearized in the neighborhood ...
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Best way to Inculde System Characterstics (e.g. Laplace Equ.) in ODE for building Control Strategy

Let's consider the following ordinary differential equation (ODE): $$ \begin{align*} \frac{\partial x}{\partial t} &= f(x,u)\\ 0 &= g(x,u)\\ y &= h(x,u) \end{align*}. $$ We denote $x\in \...
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Cascaded PID controller implementation

For a project I am building and programming my own flight controller. I have seen the implementation of a single loop PID controller. But after doing some more research I've found that a cascading PID ...
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Move a Simulated Quadcopter in a straight line

I'm trying to move a quadcopter in a simulator from (x0, y0) to (x, y) in a straight line at a constant speed. The simulator takes x and y inputs in m/s. Altitude as an input is a constant value in ...
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3-links Robot Dynamic PD Computed Torque Control

I am designing the PD control of 3-links robot using Simulink. I can't figure out what to do in the 'Robot' block to get the acceleration d_qq back to calculate the error. What is happening in this '...
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Error calculation in frenet frame

I'm trying to implement a model predictive control algorithm by using a space-based vehicle model in a road-aligned coordinate frame. I know that the lateral error in the cartesian frame can be ...
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SMC: Is there a way to control two sliding surfaces with just one control input?

This is a question related to Control Systems. I've been searching papers all over the internet with very little success. I know that traditionally we want one control per sliding surface but If ...
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control over changing data

I am trying out different control algorithms, in my practice on the state space models and control. Now I have the following system with the following states and state transitions with time. Position ...
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How is named a controller that sets a position to reach with a constant velocity?

I looked everywhere I could but didn't find a useful answer, so let me explain here: My controller is giving a position goal, and while this position is not achieved, the linear actuator is controlled ...
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From speed vector to motor control

I'm working with Mona robot (image bellow). The movement is controlled by settings the speed of each wheel. I'm trying to find a way to convert a speed vector into motor control so that the robot will ...
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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2 votes
2 answers
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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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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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1 answer
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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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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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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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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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1 answer
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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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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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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 ...
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3 votes
1 answer
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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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1 vote
2 answers
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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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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 ...
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3 votes
1 answer
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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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1 vote
1 answer
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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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2 votes
1 answer
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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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1 vote
3 answers
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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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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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