Questions tagged [control]

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

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output velocity equation of compliance control

I am trying to implement a compliance controller for a robot arm and stumbled upon an existing code snippet where the compliance velocity of the endeffector is calculated by: $v_{out} = v_{in} + \frac{...
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Examples of Zeno Behaviour in the Real World

Zeno Behaviour or Zeno Phenomenon can be informally stated as the behavior of a system making an infinite number of jumps in a finite amount of time. While this is an important Control system problem ...
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Synthesis gradient observer

I ask the advice of specialists on control systems. We have the following system. Where $u(t)$ and $y(t)$ time-varying input and output. The characteristic $y(t)=f(u(t))$ is assumed to be non-...
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Is every state space model transformable to transfer function and vice versa?

I'm looking for a mathematical proof or example of non tranformable model, and I couldn't find any.
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1answer
56 views

Is it possible to track position using gyroscope and accelerometer without a magnetometer?

I'm looking for help on a project where I will be placing sensor data in 3D space using augmented reality. Most solutions I have found for finding position with an IMU involve the magnetometer, but ...
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36 views

value of $\gamma$ in the H-infinity norm

Suppose I have the system: $\dot{x} = Ax+Bu$ $y=Cx+Du$ and the following Hamiltonian matrix: $H=\begin{pmatrix} A & \frac{1}{2}B^TB\\ -CC^T&-A \end{pmatrix}$ I want to find the value ...
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44 views

How to identificate uav's roll and pitch model and control to track object?

I'm building a drone distance controller for parrot mambo. I need to track a colored page with given distance and given heigth. I can get the yaw information from parrot mambo with 0.5 sec. Since I ...
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119 views

LQR for Inverted pendulumn

I'm studying an optimal control for the inverted pendulum in the following figure the state and the output of the system are defined as $$x=\begin{bmatrix}r & \theta & \dot{r} & \dot{\...
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44 views

What is the correct architecture of quadcopter control?

I want to make a quadcopter flight controller for my University project. Lately I was searching for systematic architecture of control system used by quadrotors. I have implemented one of the ...
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2answers
39 views

irobot create 2: random changes in driving speed

I am trying to make the Create2 dance a specific choreography. I´m not using the sensors, I just let it drive and turn for a specific amount of time. In general it works fine. But after working with ...
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28 views

Robot dynamic control

This can be a basic question but according to my knowledge I don’t know answer. We can use control system theories to control the position of motor. Considering two motor joint leg it can model and ...
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1answer
26 views

Self motion with multiple constraints

I am trying to control a 7 DOF robot (a Franka Panda). I use jacobian based control (resolved rate motion control) to generate a joint trajectory from a cartesian trajectory. My contraints for the ...
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15 views

Use polynomials to detach number of MPC controls from size of time-horizon?

Model Predictive Control (MPC) works by finding a set of controls $u_0, \dots, u_n$ that minimize a cost function $J$ over a time-horizon $[t, t + T]$. Typically when MPC is used on mobile robots, ...
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26 views

Link collision avoidance for redundant manipulator

I am trying to have my robot arm follow a trajectory while avoiding collisions between obstacles and the robot links. The way I go about it is to find the closest point on the robot arm, and treat the ...
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43 views

PD controller tuning for flexible joint robotic arm

I am trying to tune the gains of my PD controller for a single axis flexible joint robot. The controller output is the motor torque. My question is: how can i tune the PD gains if the output (torque) ...
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39 views

Constructing control system

The problem i have is more or less is biology related, but I can simplify the problem as such. I have a tank of water. I try to increase the concentration level of this tank of a certain substance (X) ...
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23 views

About the commonly used equation of distributed consensus of multi-vehicle systems, is this form correct?

$\dot \epsilon = -(L_{n}\otimes I_{m})*\epsilon$ This equation is commonly cited in works about the distributed consensus of cooperative control. In fact, it's the matrix form of the basic consensus ...
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54 views

Is it possible to make a self balancing robot using small or medium scale integrated circuits?

Almost all the information I've seen about self-balancing robots implies the use of an Arduino to implement the control. I'm wondering if it is possible to implement the control using just small or ...
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81 views

Partial CoM, the velocity Jacobian and Control

New to robotic arms here. I am currently working with a 6-DOF robotic arm shown below: I have derived the FWD Kinematics and mapped the joint angles and the resulting end-effector positions. When I ...
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40 views

Finding transfer function from bode plot

I try to estimate a system transfer function by hand calculation from a bode plot data but I could not succeed yet and I need someone help. it will be appreciated if anyone explains or refer me to a ...
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39 views

Task Space Control Parameters for 6-Dof Manipulator

I'm developing a Task Space controller based on speed for a Universal Robot 5. I've already calculated the Jacobian, position and rotation error for the classic control method: The method works fine ...
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18 views

Control Algorithms for Kinesthetic Teaching

There are several algorithms for post-processing of kinesthetically demonstrated motions for manipulators learning a task. However, I have failed to find papers/research work on modeling the ...
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45 views

TGY-6114MD Servo motor needs push to start

I currently have an inspection robot deployed in a remote part of Africa that has a failing Turnigy TGY-6114MD servo. The issue appeared randomly. The servo won't respond to commands unless given a ...
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647 views

URScript - how to get the actual TCP pose in tool space coordinate system?

I am writing a simple script for universal robots UR10 robotic arm. I am trying to find a way to to see if the tool current position is outside of a 3D bounding box. the 3D bounding box is defined ...
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26 views

Torque Disturbance Observer for Manipulator Arms

Is there a tutorial/guide apart from the research papers ( paper 1 and paper 2 ), for implementation of torque disturbance observers on multi-DOF robotic manipulators to determine sudden collision ...
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172 views

Incremental (on-the-fly) smooth trajectory interpolation algorithm from waypoints?

short version (TL;DR): I'm receiving x(t) waypoints "online", which I must travel through at the specified times. I need an algorithm that would plan a smooth trajectory in-between them without ...
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8 views

How to interpret the passivity criteria equation?

In Passivity-Based Control and Estimation in Networked Robotics (among others), a passive system is defined as one that: $$\int_0^t y^T(t)u(t) dt \geq -\beta $$ for output $y$ and input $u$. I have ...
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74 views

Why differential flatness is called “flat”?

A system is differentially flat if the state and control input can be written as functions of the flat outputs and their time derivatives. In other words, if a system is differentially flat, we can ...
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63 views

Trajectory following using LQR - Setting horizon time and intermediate points

I was going through UC Berkeley's CS287 - Advanced Robotics course. In particular - Optimal Control for Linear Dynamical Systems and Quadratic Cost (“LQR”) by Pieter Abbeel (Slide 10). Let us say we ...
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1answer
349 views

Pictures coordinates to robot coordinates

I have a picture on my C# software and the corresponding object in real world on 2d plane of motorized XY axis table. What I want is when I select a pixel on my picture, the motorized table should be ...
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52 views

Quadcopter bldc PID control

Working on stabilizing a Quad using Arduino Due. I have slightly modified one of the examples of Jeff Rowberg's library to give yaw, pitch and roll angles (zero initialized angles). Moreover, I am ...
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156 views

My robot arm vibrates during operation. Why?

Introduction: I have modeled my 5-DOF robot arm in a simulation environment to test trajectories for my physical model. I have export the joint variables from the simulation as a .csv file. Then ...
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188 views

Controls Project, Inverted Pendulum. Design issues

I am developing an inverted pendulum that uses a differential drive robot as base. The goal is to create a benchmark to practice my control using ROS, so I can implement what I learn on the Modern ...
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178 views

How can i get the Laplace Transfer function for control process for quadcopter?

I'm a beginner for quadcopter construction with PID controller and PIC 16F877 microcontroller. Now, I'm troubling with how do make the control process with mathematical model for my quadcopter :( and ...
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198 views

Accelerometer, gyro, and magnetometer sensor fusion for material resource survey

As a hardware engineer, I have studied quite a lot on sensor spec such as Accel, Gyro and Magnetometer including custom made fluxgate. I have studied matrix and quadarion (complex number) and so on. I ...
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573 views

mbed dc motor speed control using optocoupler encoder

i have been playing with mbed since few week ago and would like to create a test program for dcmotor speed control. im using a 24V dc motor with encoder attach.. then test, at first i test with ...
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130 views

What is the achievable stiffness of a impedance/admittance controlled robot (incl. haptic devices), given its structural and control stiffnesses?

EDIT: I realised I missed the point of the paper completely (thanks to very-skim reading ;) ). So, this part of it I'm relating to is about how much damping - not how much stiffness - should we ...
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213 views

Quadcopter force/torques duty cycle conversion

after having been determined my control loops for my quadcopter project, I'm going to determine the motor commands (PWM duty cycle) from the motor forces/torques. I was following the guidelines of ...
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4k views

accelerate a stepper using arduino AccelStepper starting with a pre-defined speed

I've read the AccelStepper documentation on airspayce.com and it seems to be not possible to accelerate a stepper starting with a speed greater 0. Acceleration always starts from speed=0, I tried it ...
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111 views

How to select the parameters of the Sliding Mode Control of a Robotic Arm?

I working on sliding mode control (SMC) of a 4 DoF manipulator, I don't know how to select the discontinuity gain matrix, $ K$ , the surface constant (the diagonal gain matrix $\Lambda$ components).
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control a robot with pymorse on MORSE simulator question

I am new to Morse and robotics. This code control the robot by giving the linear and angular velocity. This is the scene description ...
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94 views

Quadcopter one beep and blink problem

I have just built my first quadcopter, and have run into a bit of a snag. When I plug in the power, I only get one beep and a red blink from the flight control board, and nothing else happens. When I ...
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85 views

McKibben artificial muscles and the 400:1 ratio

I was recently reading that those artificial muscles had the highest power/weight ratio while electric motors only have a ratio of less than 100:1. As electrical engineer I have never worked with ...
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85 views

How do i use the Nicolas ziegel approach if my system never becomes unstable?

How do i use the Nicolas Ziegel approach when the root locus plot of my system never becomes marginally stable , for any gain (unless it is negative).. ?? How do i estimate my ultimate gain value????
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VAL language and velocity control of industrial robot

In my bachelor, I programmed CNC machines. Now, working with an Industrial robot arm, I learn that their programming languages are mostly similar. VAL is a typical example, for instance: ...
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1answer
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Error in Pose(): All values are zero for turtlesim/Pose

Here is the program I have written. The function is to make the turtlesim complete one revolution, with a fixed angular velocity and speed. ...
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1answer
18 views

Understanding across gravity compensation, demonstration (Kinesthetic Teaching vs. Teleoperation) and inverse dynamics

I first state my humble probably wrong opinion on the connection of these concepts: In gravity compensation mode, each joint has equilibrium as its set point, a human demonstrator can effortlessly ...
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Imaginary part in result of inverse laplace transform

I am working with a system(closed-loop feedback control) that has a transfer function like this F = 20*(s+5)/(s^4+13.5s^3+41s^2+80*s+100) this one is in the s-domain but for the response analysis, I ...
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1answer
17 views

Rotary Stage (high resolution controller for BLDC motor)

I am building a 3phase BLDC motor controller based on an STM32 MCU, a high resolution 26 bit optical encoder and a DRV8301 motor driver from TI. This is a for a high precision rotary stage for an ...
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Relation between control and reinforcement learning

Has the relation between Control and reinforcement learning been studied by the scientific community? I would like to read credible studies about each ones pros and cons when it comes to control ...