Questions tagged [control]
A method or device to manage, command or regulate some part of a system.
414 questions
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Robotic Arm Senior Capstone. Electronics/Controls/Sensors Questions
I am a mechanical engineering student currently working on my senior capstone. My team of all MechEs has to build a robotic "arm" where the arm is really just a link/bar of aluminum. The thing we ...
2
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0answers
26 views
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 ...
2
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3answers
44 views
Benfit of behaviors & benefit of hybrid systems
I have two questions that I think are closely related:
Why is it useful to introduce behaviors, e.g., goal-to-goal + obstacle avoidance? (The alternative would have been to just use a single behavior ...
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0answers
39 views
+50
weired actuator position plot
I am trying to design an MPC controller to control the velocity of an actuator. The robot is inside a pipe to inspect the pipe.
My input for this system is PWM and output is the velocity of the ...
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1answer
22 views
What limits the observer eigenvalues size?
IIUC, the recommendation here of increasing the absolute size of the real part of observer eigenvalues is based on two factors:
We want the observer to be updated as fast as possible (I suppose up to ...
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0answers
15 views
Hover control for quadcopter doubt?
For my project I need to make a hover control using state space approach for a quadcopter. So far I have taken a non linear state space model from a research paper that used 12 states, 4 inputs and ...
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0answers
21 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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5answers
107 views
Why we want to write all linear system into form of first order differential equations?
It seems to be taken granted that when we deal with some control system, the first thing we want to do is to linearize the system and put it in form of first order differential equations like $\dot x =...
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3answers
46 views
PID and Kalman filters
Both PID and Kalman filters are used extensively in Robotics. I gather, Kalman filters for sensing and PID for control. What is the mathematical, statistical or other relationship between them?
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1answer
42 views
How to implement a novel control algorithm for a drone
I and my research team are working on a novel drone design based on trirotor. The difference between this design and a trirotor is that it has an extra propeller to generate additional thrust, ...
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1answer
23 views
How many independent control inputs does a hexarotor have?
6, because a rigid body has six degrees of freedom
4, since it is similar to a quadrotor, except with more motors
6, because there are six motors
I was taking an online quiz, and I thought option 3 ...
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0answers
6 views
where to apply state space model, controllability, observability and pole placement in robotics?
In a course named modern control systems I have just finished learning:
State models for LTI systems
Diagnolization
Solution of state equations
Controllabilty & Observability
Pole ...
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1answer
36 views
PID control related to lagrange equation
I'm a beginner in robotics and so far followed the lecture series by Prof. Oussama Khatib and some blogs and papers. currently I'm following this studywolf blog. in the end I plan on building a simple ...
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2answers
67 views
Problem with tuning PID for motor
I am trying to tune my PID to make my motor have a consistent output:
input(pidOutput) => 100rpm
I used the following step to tune my PID:
Set all gains to zero.
Increase the P gain until ...
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0answers
13 views
Help required using hammerstein weiner model implementation in simulink
I have identified a 2 inputs 1 output (MISO) model using Hammerstein weiner model with the System Identification toolbox.
Now, I wish to implement the identified idnarlx model into a generic ...
3
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2answers
44 views
Meaning of a negative step response with quaternion
It's not technically robotics but:
I've been trying to reproduce in Simulink a spacecraft attitude simulation using quaternions, and the kinematics and dynamics seem to work fine, however I'm having ...
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1answer
37 views
stable altitude quadcopter
I'm currently working on a project to generate a stable altitude and automatic control for a quadcopter
I'm using arduino as the flight controller
Ultrasonic sensor HC-SR04
MPU-6050
However my ...
1
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1answer
48 views
Quad-rotor 1-D Linear Control Simulation with MATLAB
I was Performing Programming Assignment with MATLAB for Quad Thrust and Height for an Introductory Course. The control input for a PD controller was According to the Equation
u = mass*(diff(s_des, 2)...
2
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1answer
27 views
How can I limit the current sent to my 6V servos to ensure they don't burn out?
I'm using an adjustable desktop power supply (0-30 volt DC, 0-10 amp) to power my robot which has 7 standard 6-volt servos. There are some situations where the robot gets jammed, and power draw ...
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1answer
31 views
Could a quadrocopter still be controllable if its payload was wider than the quadrocopter?
Lets say a quadrocopter's rotors are 2 feet apart, and 2 feet beneath it is attached a symmetrical, balanced payload that was x feet wide (with space for air from the rotors to move through) - if the ...
2
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1answer
30 views
Creating linear end effector motion using joint speeds: Converting tool speed to joint speeds
Background Information: I'm new to robotics and my school currently has access to a 6DOF Universal Robot (UR-10). I'm programming it using its scripting language URscript and the arm has these two ...
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0answers
18 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
63 views
Control Pneumatic Cylinder Position with Potentiometer and Analog Comparator on Arduino Uno
I am building a robot arm that is actuated by a pneumatic cylinder. Extending and retracting the piston would increase and decrease the joint angle respectively. This is done using a 5/3 solenoid ...
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1answer
50 views
Math behind trajectory 2d planning
I have a case of a differential drive robot and a control system in a two-dimensional environment:
Now the problem: we would like to make our particle move from point A to point B, and from there to ...
2
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1answer
62 views
Is orocos dead?
We are using orocos on the robot we have been developing for 3 years now and I have the feeling that Orocos is no longer maintained and the mailing lists are not only no longer active but also it is ...
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0answers
23 views
Sensored BLDC motor (sometimes) needs push to get started
I'm having a sensored BLDC motor (12V version though) connected to a suitable motor controller and powered through a 25A regulated power supply With an Arduino I'm able to control the motor just fine. ...
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1answer
23 views
Motorised Stage for laser
The problem
I want to be able to move the direction a laser is pointing.
This means I need to have motorised rotation of the laser head in the x direction and in the y direction. I am unsure of the ...
1
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1answer
84 views
Alternatives to Finite State Machines (FSM's)?
In Udacity's Self-Driving Car Engineer online course, one instructor claims that "[Finite State Machines are] not necessarily the most common [approach for behavior planning] anymore, for reasons we ...
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1answer
60 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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2answers
37 views
Pole placement of the observer closed loop system (A-LC) in discrete system
*I'm rewriting the question after I deleted the previous one because I wasn't clear enough. Hope it's fair
Given a system of the general form:
\begin{align}
x_{[k+1]} &= A\,x_{[k]} + B\,u_{[k]} \...
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2answers
104 views
Dynamic model using identification for control
I'm currently working of a 5 DOF robot, for which i'd like to compute the dynamic model through identification. I have experimental data representing torques (inputs) and positions (outputs). How can ...
0
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1answer
40 views
zero-g mode for UR10 gravity compensation
I would like to freely move my UR10 arm in response to an external force, just like the zero-g mode for Baxter robot, which can be activated by holding its wrist. The Baxter documentation on zero-g ...
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0answers
38 views
LQR Robotic Arm
I have a robotic arm model in Simulink and I'd like to control the position of the end-effector such that it follows a given trajectory. This is done by inputting joint angles and comparing the output ...
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1answer
27 views
Obstacle Avoidance: Detection of goal inside the obstacle
It is easy to understand how a robot can avoid obstacle if the goal point is not within the obstacle (Point A) as shown in the figure. But I'm curious how could a robot know that the the goal point is ...
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1answer
42 views
Inter-robot Collision Avoidance
I try to understand some MATLAB code (see below) i found from the web for inter-robot collision avoidance. But I'm not really understand, how the theory behind this code work. Can anyone help me ...
0
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1answer
78 views
Quadcopter mathematical model and controller design
if we just examine the translational dynamics (X and Y direction), the dynamics are coupled, So if I want to design a PID controller to control the position, the outcome will be unpredictable because ...
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0answers
13 views
Simulation of error in following trajectory for robot manipulator
I am working on a surgical manipulator project where I have optimized the link lengths of the manipulator for maximum isotropy. Does the maximum isotropy reduces the error in following predefined ...
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0answers
19 views
Designing systems for sharing resources on multiple SOC's
I have some Raspberry Pi's from previous projects/learning and I would like to pool their resources to make a differential drive robot.
Two Pi's would have one camera each for a vision system, one ...
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0answers
9 views
How to determine sampling time, acceptable dead-time to reject output disturbances in FO- and SOPDT models?
I have a few questions regarding sampling time, dead-time, and output disturbance rejection.
Given a typical first-order plus dead-time model:
$$P = {Kexp^{-sL} \over T_ps+1}.$$
I would like to ...
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0answers
36 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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0answers
11 views
Driver requirements to control reaction force
I have a cable that is rigidly attached at one end and connected to the robot arm (UR10) effector at the other end.
I would like to increase the tension in the cable by pulling the robot effector. ...
0
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1answer
49 views
State space model
I want to design a LQR controller for my two wheeled mobile robot. While designing the controller, I need to find gain, K for the LQR which this required the state space model of wheeled mobile robot. ...
2
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0answers
15 views
Torque commands for velocity reference motor
I have a controller board for a motor, where I can read the motor current (to transform to torque), the position, the velocity and I can give a velocity command. There is not really a torque mode on ...
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0answers
12 views
Some Question about TOSHIBA robot
TS Series robot
what is the "Point Position"
what is the "posture"
I want to know what the meaning of each location information means.
6-axis (x,y,z,a,b,c,u,v)
SCARA (x,y,z,c,t)
what is the "...
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0answers
42 views
Creating transfer FNC
im working on controlling a 2 link arm with simulink, and wanted to try torque control.
I've built a trajectory generation function in matlab and it gives me the position that the joint needs to be in ...
0
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2answers
35 views
Controlling a servocity planetary motor?
I know this might sound like a stupid question, but I actually need help with this. So, I'm looking at this motor: https://www.servocity.com/2737-rpm-premium-planetary-gear-motor.
I have a raspberry ...
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2answers
61 views
How to start as a control system engineer and to make advanced projects using PID [closed]
I am new to the field of control systems, PID and robotics and I want to enhance my knowledge in the field. Can you recommend me books where I can start learning about control system engineering (with ...
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0answers
24 views
Linear Actuator
I'm having some technical issues with the SDA6-263 and SDA12-263. The problem I'm having is the same for both actuators.
This is the list of my equipment for my setup.
Sabertooth 2x32 (https://www....
2
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1answer
45 views
Making a tunnel follower robot with 2 IR side sensors and 1 ultrasonic sensor
We have a tunnel and the distance from the walls to the robot is about 30cm when the robot is centered, the tunnel curves to the right. The robot has an infrared sensor on its left and one on its ...
1
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1answer
36 views
Strange phase case in Bode diagram of a transfer function [closed]
Please help me to solve my problem:
This is the transfer function: $G(s)=10\frac{(s^2+1)(s-10)}{s(s+0.1)(s^2+2s+100)}$
I calculated properly the whole Bode diagram apart from the phase of the complex ...
