Questions tagged [control]
A method or device to manage, command or regulate some part of a system.
603
questions
2
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1answer
20 views
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 ...
1
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2answers
68 views
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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0answers
21 views
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 ...
2
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0answers
37 views
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 ...
1
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1answer
65 views
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 ...
2
votes
1answer
57 views
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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3answers
52 views
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 ...
0
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0answers
28 views
Can the PCB Circuit Board be removed and replaced from inside the Create 2: Programmable Robot? [duplicate]
For a school project, the professor wanted to know if needed that the PCB Circuit Board could be removed.
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0answers
22 views
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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3answers
69 views
Servos jittering problem
So I started building this 3D printed Bluetooth robotic arm that can be controlled via MIT app inventor from HowToMechatronics.com. After connecting all the servos and running the code, the servos ...
1
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2answers
35 views
Is there a way to send commands to the Staubli CS9 from remote system via TCP/IP??(like ur_rtde, urx libraries for UR robots)
I am new to ROS development and Staubli robots. Though i have some prior knowledge on UR5e, I am finding it hard to understand the architecture of Staubli and its other programming interfaces (like ...
0
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1answer
40 views
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 ...
0
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1answer
49 views
How to design a PID controller for boat?
I have a boat with two trusters and a trajectory planner which is based on the bicycle model. In order to control the boat, the linear velocity of each truster has to be provided.
The following ...
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0answers
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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0answers
21 views
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
53 views
Multidimensional obstacle avoidance
Artificial potential barriers are known that allow robots to avoid obstacles. They are constructed as follows. https://authors.library.caltech.edu/106548/1/2010.09819.pdf
Can you please tell me how ...
0
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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 ...
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0answers
21 views
Looking for a course (online?) RE: systems with XY stages
Using XY stages is common in many fields:
3D printing
Genetics instruments
semiconductor lithography
automated microscope slide imaging
See for example https://www.asml.com/en/technology/lithography-...
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0answers
17 views
Fuzzy Path Planning for an Unknown Environment
I have a problem to programming on Matlab the path planning fuzzy in an unknown environment I am using a fuzzy toolbox for fuzzy rule
How to do obstacle avoid by Matlab demo program
How to reach the ...
0
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1answer
58 views
Robots Following Robots with Safety Distance Planning and Coordination
I have two robots, I wish for the second robot to follow the first one while keeping a constant distance d_safe between them. I am trying to implement a PID ...
0
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0answers
17 views
MAVLink data stream to third-party system
I'm a completely beginner with pixhawk and MAVLink. So I want MAVLink (via AP Mission Planner) to send vehicle data e.g. attitude etc. in real-time to a third-party system that has a built-in ...
1
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0answers
25 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 ...
0
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0answers
43 views
Find viscous friction for DC motor transfer function
How do I find the viscous friction for my DC motor without measuring the input current and output torque.
I have to do a theoretical model on simulink and can't find any answers on how to find it
2
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2answers
50 views
How to investigate the relation between planning frequency and control response?
I have a speed control system which is part of a hierarchical planning and control stack. The final output of this system is torque and the input is desired speed. The system is experiencing some ...
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0answers
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 ...
2
votes
1answer
70 views
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/...
1
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1answer
57 views
How to choose closest angle when crossing -180 degrees
I'm applying a PID for position control on a diff drive robot, got the angles (orientation )between -pi and pi. It works fine until it needs to change its orientation from (let's say) -170 degrees to ...
0
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1answer
50 views
Is it possible to solely use a P-controller for velocity control?
Let's say I want a robot to run at a certain speed. I have one motor attached to each robot rear wheel. The feedback value to the controller comes from an encoder, which outputs pulses per time unit, ...
1
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1answer
56 views
Velocity-Control of a manipulator without a dynamic model
I have a five DoF robot. Each axis is connected to a cylinder. You can send PWM values to each cylinder and you are able to read out the position values of each cylinder which makes it possible to ...
0
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1answer
58 views
Help on the Walking without thinking about it paper!
I was reading the paper, which you can find: https://hal.inria.fr/inria-00567668/document. I got so confused with equation (33) and (34), it seems like instead of an equal sign in eq.(33) on the left ...
0
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1answer
52 views
Do hobby servos respond to step inputs with a step in torque?
I'm designing a piston that I need to expand a few cm in <100ms to load energy into a spring-mass system with around a pound of force (as shown below). Based on power specs alone, high-end hobby ...
3
votes
2answers
353 views
Impedance Control vs Position Control
I have been reading up on impedance control, and several sources have stated that it is much safer than position control. However, frustratingly, none of these sources have explained why this is. So......
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1answer
33 views
How to estimate gradient of Jerk
A trajectory is described by a position vector, i.e., traj = $[q_0, q_1,...,q_n]$. The objective is to minimize the jerk of the trajectory.
I am referring to this code to understand how the gradient ...
2
votes
1answer
36 views
Control signal of an LQR Controller
I'm working on building an LQR for a system which consists of a ball in a vertical tube, a fan is situated at the bottom of the tube and a distance sensor is at the top, a raspberry Pi is used to send ...
0
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0answers
57 views
Path curvature in kinematic bicycle model
I'm trying to develop an understanding of the control law for longitudinal and lateral control for self driving cars. While doing so, I came across the kinematic bicycle model which is used to derive ...
0
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1answer
26 views
How to simulate a system output with a sine wave input?
I wish to simulate the output of a certain gear system I have. How the gear system looks isn't particularly important to the problem, I managed to get the differential equation needed from the ...
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0answers
45 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 ...
0
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1answer
86 views
Does the Grbl have S-curve or harmonic velocity profiles?
I'm working on a machine and the position has a high impact by the jerk and acceleration of the machine. I'm using Grbl for my machine. Does Grbl has S-curve or Harmonic velocity profiles?
2
votes
1answer
71 views
What can cause yaw rotation on a multirotor when yaw control is disabled?
Let's assume that I assembled a multicopter (quadcopter, hexacopter or octocopter) and let's say that I disable yaw control on it while roll and pitch controllers are enabled.
Now let's assume that I ...
3
votes
2answers
82 views
PID Control: Is adding a delay before the next loop a good idea?
I am implementing PID control in c++ to make a differential drive robot turn an accurate number of degrees, but I am having many issues.
Exiting control loop early due to fast loop runtime
If the ...
0
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0answers
30 views
Is Image Based Visual Servoing a non-linear controller?
Is Image Based Visual Servoing a non-linear controller? I think it is as the Image Jacobian has square terms of u & v (image-plane coords).
Where $p_u, p_v$ are the width & height of each ...
2
votes
1answer
27 views
Dynamics with error term
How do the dynamics of a system change when an error term is introduced?
For instance, if I have a system (computed torque control - robot manipulator):
$$M\ddot{q} + C\dot{q} + G = u$$
and $e = q-q_{...
2
votes
3answers
70 views
How to obtain the state space representation of a computed torque control system?
Assuming I have a system:
$$
a \, \ddot{x}_1 + b \, \ddot{x}_2 + c \,\dot{x_1} + d \,\dot{x_2} + e = u_1 \\
f \, \ddot{x}_1 + g \, \ddot{x}_2 + h \,\dot{x_1} + i \,\dot{x_2} + j = u_2
$$
How would I ...
0
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2answers
54 views
High derivative gain in PD control
Why does high derivative gain in PD control results in motor noise or chatter?
The graph that I see on MATLAB simulation is smooth enough, so following that it should not make noise..
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1answer
41 views
How do I compute the feedforward terms in a control law using Matlab?
I have the following situation. I have computed the linear and angular velocity which are the controls for a mobile robot, which have the form:
$v_d=v_{fb}+v_{ff}$
$\omega_d=\omega_{fb}+\omega_{ff}$
...
0
votes
1answer
224 views
How can I define the saturation function in Matlab?
I would like to write a Matlab code for an angular velocity of this type:
$\omega=\omega_{fb}+sat(\omega_{ff})$
where $\omega_{fb}$ is a feedback angular velocity and $\omega_{ff}$ is a feedforward ...
1
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2answers
159 views
How to consider gravity for the state space modeling
I'm trying to find the state-space model of the following ball-in-tube system.
I designed the SISO system, with the h(ball height), w(angular velocity of propeller), and I(current) as the system ...
0
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1answer
36 views
Control method advice for Markov (?) process
I'm experimenting with a device for tuning piano strings. It attaches to the piano's tuning pins and turns them slightly by applying a torque impulse. It is a semi-automatic process, handled by a ...
0
votes
1answer
39 views
Matlab code to take time derivatives
I have a velocity command, which is:
$v=k_1\rho cos(\alpha)$
where each quantity $\rho$ and $\alpha$ depend by the time.
I would like now to take the time derivative of this, in order to use it as ...
0
votes
1answer
33 views
What is the difference between The state-space equation and The configuration-space equation
The craig(p.180) states that equations can be made to represent the dynamic equations. The first one being the state space equation.
$\tau=M(\Theta)\cdot\ddot{\Theta} + V(\Theta,\dot{\Theta}) + G(\...
