Questions tagged [control]

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

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Multivariable PID controller

I'm making a robot that uses two DC motors to move, and has two distance sensors on its right side. I want to make a PID controller to control the angle of the robot (using a wall as reference) and ...
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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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1answer
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How to find angular velocity using pure pursuit algorithm?

I have implemented the pure pursuit algorithm for my differential wheeled robot as described in the following paper: http://www.enseignement.polytechnique.fr/profs/informatique/Eric.Goubault/MRIS/...
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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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51 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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0answers
123 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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Data gathering and selling

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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27 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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21 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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15 views

Is there a way I can achieve Torque control from pulse control?

I am using the Contec SMC-8DL Motion control card to control the Oriental Stepper motors via the AZD-C driver. The Contec helper functions only allow for sending pulses to the driver, is there a way ...
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44 views

Kalman filter for visual tracking of a ball sliding on a gutter

I'm working on a project where a robot needs to keep a ball at a desired position on a gutter. The gutter is fixed at one end and held at the other end by the robot’s ...
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35 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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16 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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32 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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0answers
58 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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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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56 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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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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51 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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0answers
734 views

moveit! trajectory execution aborted

I'm trying to send a custom arm to a pose through moveit_commander_cmdline.py, it fails after sending to the said pose using " go default_pose" and returns an error. ...
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45 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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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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66 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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845 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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1answer
206 views

Controlling YuMi robot by serial port

I'm trying to control the YuMi robot arm by a serial port. The serial port will give the information on what direction the end-effector should move and what is the velocity. What I would like to ...
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31 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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222 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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100 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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71 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
411 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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58 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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166 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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222 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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0answers
183 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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201 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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617 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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134 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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220 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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0answers
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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115 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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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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89 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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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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Can the PCB Circuit Board be removed and replaced from inside the Create 2: Programmable Robot?

For a school project, the professor wanted to know if needed that the PCB Circuit Board could be removed.
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1answer
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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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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
35 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 ...