Questions tagged [control]

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

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1answer
21 views

Max motor voltage for RoboClaw controller

The RoboClaw data sheet from ServoCity mentions various current limits, but what about voltage? Can I run a 110 Vdc treadmill motor?
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1answer
25 views

Sampling time selection

I'm trying to design a compensator for a pendulum type plant with arduino mega. As you can see from the picture, the system bandwidth is 9 rad/sec. I calculated the sampling time as ws=10*wb=90, so, ...
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1answer
23 views

PID control: zero out integral on error sign change?

I am learning about PID as a novice to robotics (background in software engineering). One common problem with PID is that if the PV is below the SP for a long time, integral term will accumulate a ...
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25 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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1answer
19 views

Joint torque sensor vs end-effector force sensor

I am trying to understand the difference between joint torque sensors, and force sensors, in a robot arm. From what I understand, joint torque sensors estimate the torque at each joint, whereas a ...
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1answer
24 views

Transform this matrix of distances into a more general one

I need to make the navigation and guidance of a vehicle (a quadcopter) in a platform. This platform can be seen like this: where the blue dots are the center of each square, and the $x$ distances are ...
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34 views

Force Controller for robotic manipulation

I want to implement a force controller but I don't understand some concepts here. I saw some books that say the output torque command of the force controller and the impedance controller will be ...
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16 views

Trajectory tracking problem for non-holonomic mobile robots

Currently, I am working on the trajectory tracking problems of autonomous ground vehicle and a little confused about the applicability of control theory for different types of wheeled mobile robots. ...
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2answers
58 views

Which controller (PI or PD) is generally more robust to noisy sensor measurements and why?

Assuming no filter is used to measure error (or rate of change in error) with respect to a desired state, would a PI controller more/less/about equally robust to signal input noise compared to a PD ...
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44 views

PID control loop and feedback acquisition synchronization

In many real-time PID control loop application I have seen that the control loop is triggered exactly as the ADC interrupts arrives in order to achieve maximum synchronization between feedback ...
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1answer
22 views

When are non-diagonal matrices advantageous for linear quadratic regulators?

When setting up an optimal control problem using a linear quadratic regulator, one often chooses semi-definite matrices Q and R such that the objective function J has the form $$J=\int_{t_0}^{t_f}(...
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1answer
30 views

What is Natural Navigation?

While going through this Page on different types of navigations used in AGV's for Industrial Environments. I came across natural navigation which claims to reduce installation time and cost for the ...
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2answers
48 views

PID control while desiring steady state offset

I have a rather niche application of PID control, and I am looking for ideas on how to solve it. Design Temperature sensor is externally mounted on a liquid vessel's body --> ...
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1answer
67 views

What are the differences between trajectory planning, trajectory tracking, path planning, path following and motion planning?

What are the differences between trajectory planning, trajectory tracking, path planning, path following and motion planning? And what are the basic methods they use?
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1answer
29 views

Force controller with feedback issues

I'm implementing a force controller on a robotic arm, where the force input comes from torque sensors in the joints. I have calculated the cartesian force on the end-effector from the joint torques, ...
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1answer
46 views

Feedback linearization of a nonlinear MIMO system

I have to design a feedback linearization for the model of a car with a single trailer. This picture shows the system: And this is the kinematic model I got, where ...
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1answer
41 views

Kalman Filter: Do we need to measure each entry of the output-sequence, or can we derive them?

A Kalman-Filter gets applied to a state-space model in order to obtain estimates of the state-vector. Example: Assume a car moving on a straight line in x-direction (this is a 1-dimensional problem)....
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29 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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25 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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1answer
50 views

Why do I need impedance control?

I am having a hard time understanding the impedance controller. I see that it looks at the manipulator as impedance and the environment as admittance. However, it is hard to grasp the concept and ...
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1answer
24 views

Design a robot that can apply hot glue to paper

I need to automate a process that involves applying hot glue to paper. I own a standard handheld hot glue gun, like this one: Sticks of room-temperature glue are fed in the right side. Pulling the ...
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1answer
92 views

Why is the Kalman filter a filter and not a control system?

Why is the Kalman filter a filter and not a control system? The Kalman filter is a recursive filter which can be used to estimate the internal state of a linear dynamic system with noise in the signal(...
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16 views

increase of sensitivity bandwidth with H-infinity optimization

I have defined a defined a controller using the H-infinity optimization in Matlab using just the sensitivity weigth in the following way: ...
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44 views

Real-time python reinforcement learning library

I'm looking for a reinforcement learning library that can be used for real-time robot control. What I first had in mind was ROS to describe the robot, Mujoco to simulate physics, and OpenAI gym to ...
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14 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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29 views

How to add some more feature for this simulink model

After some research Robotic hand simulation in MatLab? After some motivation, I have tried to go inside Matlab Simulink and was able to do this :- https://drive.google.com/open?id=...
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1answer
30 views

Image based visual servoing for quadrotor forward flight

I'm still trying to understand how to implement image based visual servoing (IBVS) for quadrotor. The control laws seem straightforward if you want to use IBVS to track a feature in the image space at ...
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33 views

How to find Q and R in the Kalman filter according to known noise information?

My team built this linearized model in Simulink which works pretty well. I am currently building a continuous kalman filter. I assume some noise disturbance in the input and the measurement like what ...
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27 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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1answer
63 views

Is there a more accurate feedback loop with less overshoot or disturbances than PID?

So I was starting a robotics project and turns out that PID hasn't served very well in the past. So I was wondering if there was another feedback loop mechanism which has less overshoot and is more ...
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1answer
43 views

Add control and planning trajectory to double pendulum [closed]

How do I control a double pendulum to get the end effector link to go in the trajectory shaped in a perfect circle? I have the equation of the circle to go in but I don't know how to get the double ...
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23 views

Rigid body system identification with machine learning, but how?

Most problems in robotics have to do with a controlling a system. An easy example for a system is the forward kinematic of a robot arm. A joint in the model gets a certain value, and as the result the ...
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2answers
77 views

Robotic hand simulation in MatLab?

We are doing graduation project and require simulation of the robotic hand to be submitted. And we want to control various parameter in for movement for fingers of robotic hand. We tried it in other ...
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1answer
238 views

How to limit large acceleration and jerk from PID controller?

I am trying to control a robotic arm with force input. The output of the force sensor is filtered, and fed through a PID controller to command the end-effector velocity. However, the robotic arm has ...
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24 views

Overcoming or managing deadband in vehicle steering controller [duplicate]

I found out there is a deadband in my steering controller after several runs. And the transfer function for it in the \$s\$-domain is $$ H(s)=\frac{270\cdot e^{-0.03s}}{0.015\cdot s + 1} $$ To ...
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38 views

Are examples for jerking robotarms available?

I'm trying to find some youtube videos which are showing robot arms with some malfunction in it. The problem is, that the keyword is unclear. Should i search for “unstable”, “tremble”, “jerking” or “...
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1answer
54 views

motor controlled lazy susan

I'm trying to figure out an easy lazy susan setup. This is for video production, I want to be able to put an object on the platter and get a smooth consistent turn in order to shoot the object ...
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1answer
57 views

What is a Velocity Smoother?

I'm learning ROS and I have found an expression that I don't understand. I'm reading the book "Mastering ROS for Robotics Programming - Second Edition", and on a controller to move a robot using ...
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1answer
38 views

Is system identification and a physics engine the same?

In the control theory the term “system identification” is used quite often. A typical sentence in a robotics oriented paper is that the author is trying to “build a model of a plant with matlab”. The ...
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1answer
68 views

Quaternion error in one degree of freedom

I would like to control a system which orientation I measure with as quaternion based EKF in one degree of freedom. Obviously the simplest thing would be to convert the quaternion estimate to euler ...
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1answer
52 views

Input/output linearization

I am studying the book "B. Sicilliano -Robotics. Modelling, Planning and Control" chapter 11, Input/output linearization topic. Where does the formula for theta in 11.75 come from? In the case of the ...
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2answers
55 views

I must determine the resolution of a control system when using an 8-bit encoder for a single-rotation joint

The length of the link is 50 cm and the arm moves 180 degrees. Can anyone help me? Out of the cosine theorem, $d = \ell \sqrt{2\left(\ell-cos\right)}$, I calculated the distance traveled by a linear ...
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2answers
137 views

What are the equations of a s-curve position path?

I have a decoupled mechatronic system with two motors. I want for each motor to give a s-curve path as reference. You can see in the image below the position path, velocity and acceleration. All ...
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0answers
188 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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3answers
109 views

State Space model for bouncing ball

In lecture 5.5 Bouncing ball, slide 26, Coursera's Control of Mobile Robot course, how are the state space equations formed in "Equations of motion in-between bounces"? Why is [0 -g] added? And how ...
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20 views

Can I combine BEAM robotics with fuzzy control?

Beam robotics invented by Mark W. Tilden is about analog circuits for controlling robots. The idea is to avoid microcontrollers and software and use instead resistors, breadboards and capacitor for ...
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2answers
113 views

How to approach any advanced control problem in robotics

I have worked on a couple of projects like control of a quadrotor/ self balancing robot/ 6 dof robotic arm using nonlinear, optimal and adaptive control. So, in all these projects I have first ...
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1answer
37 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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2answers
34 views

State-vector for distance measurement between two autonomous cars

I hope someone can help me: Given two autonomously driving cars, I want to make sure they keep a constant distance to each other. For this purpose, I want to design a Kalmanfilter. Typically, the ...
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2answers
28 views

Vertically moving robot

I want to build a 4WD robot that can travel vertically by pushing against opposite rails. The wheels push against the rails and generate friction, the robot moves upwards as the wheels rotate. This is ...