Getting started with Motion Simulation Control Basics ... How it works ?

As a start ... motion control systems is what I call it Electro-Mechanical Compo Balanced Systems.
And a predefined DOF "Degree Of Freedom" expression is used for motion control system between point A to point B ... even in curved motion direction .
So Motion Controller boards as master brain are like "SimAxe ,Arduino ,... "

To build Such DOF system we must have a balanced system ... which by default and is divided into two sides the mechanical motion side ... and electrical control side ... with a kind of internal communication way between them ... with a basic responsibility for both sides to watch the other side and a brain to react .

Each side has a balanced bond between two points, So we have the mechanical motion bond points and the electrical control bond points ... So we have total 4 points 2 on each side ...
The Brain "processor " always compare these bond points in pair and uses the communication way between sides to check each bond and there is NO Deference in its points ... plus giving orders to correct the unbalanced points ... So bond points must gives a "Zero error " measurement result in there own type of construction concept level ... eventually we'll get a stationary alive system .

• The electrical control bond points names are "set point" & "new set point" as digital values for the electrical control side ...
• The mechanical motion side points names are "motor shaft angle" & "Feedback pot shaft angle" for the mechanical motion side ...
• Since the communication way between sides is electrically presented in signal/s ... the "Feedback pot shaft angle" value is only converted into an electrical signal called "Feedback signal" ... the motor driving commands from electrical control side are called "motor signals" ... the computer commands is sent and received through a USB data link .

-Mechanical side drive method: in the next video (Is not exactly what we're talking about ...but just a simple outline help)... explains how the system corrects itself if the mechanical bond side is unbalanced by making an angle deference between the pot axes and the motor axes ... while the set point and the new set point remains equal in the electrical control side ...

the motor rotates where the pot rotates to ... and corrects that angle to zero or " follow-up mechanical DOF" ...

-Electrical side drive method: is what motion simulator in our XSimulator.net " DIY Motion Simulator Kit " are using with some basic concepts ...

• first concept here we are mounting back again the Feedback pot shaft with the motor shaft permanently by an appropriate decent mechanical way regarding the simulator design that is providing a certain range of motion ... this mechanical bond side form the balanced system remain FOR EVER with no mechanical error ... so actually we are reading the motor shaft angle as a variation of the feedback bot resistor as a Feedback signal
• Second basic concept ... digitally convert and consider the" Feedback signal "as the " set point " value in the processor so this Mechanical Communication Electrical bond is FOR EVER too ... So IF [set point = Feedback signal = motor shaft angle ] ... All are equal with no deference or the error equal zero ... every thing remains stationary ...

So in such motion control system ... digital values are transferred through the input/output connections of the controller board ... Some extra LCD display output connection may be added to the board for tracking proposes only ... Information is provided to the processor as above through the USB data link from the attached PC to be the new set point ... as values from the feedback pot is considered set point ... .

Now we unbalance or "Drive " this electrical DOF system ... giving the new set point another value to make an error in the electrical side ... as hundreds of commands presenting a "new set point " per second is sent to the controller processor here what is happening ... Next steps are actually happens very very fast in real time so get ready :

1. IF we send from the program on PC a " new set point" value to processor. So compared with the "feedback set point " coming from the feedback pot there will be difference +/- in the electrical control bond side ...
2. Assuming it is positive deference ... then processor gives orders through output communication to the motor to rotate CW ... Regarding that feedback pot shaft mechanically mounted to motor shaft ... that CW rotation will give a "feedback set point" to the processor which while motor CW moving it is continuously compared with the " new set point " required value until " error = zero " ... then motor stop .
3. Vise Versa for Negative deference ... then processor gives orders through output communication to the motor to rotate CCW ... regarding that feedback pot shaft mechanically mounted to motor shaft ... that CCW rotation will give a "feedback set point" to the processor which while motor CCW moving it is continuously compared with the " new set point " required value until " error = zero " ... then motor stop .

These three simple steps are done quickly and with further more details [for programmers ] in position approach that are called PID control ... which gives a smooth fast start fast stop as required on target .



For driving a wheel rolling in a straight distance from 0m.m. to 100m.m. which is called "range of motion " ... and if we have only 100 set points that called " linear motion resolution" ...
So the system can't set you on any fraction of the range ... we use higher resolution set points ... So we get smother motion along the motion range and will not notice the little jump differences between the set points ... the same concept applies to a 180 or 360 degree rotation arm as radial motion ... these items are solved pretty good in the SimTools Free Motion Control Program in this site ...


For the next video it shows how we as humans doing this as we are driving a car or throw the dart and look where it goes and then correct our next strike depending on our shoulder position adjustment resolution ... and our Brain calculations .





Resolution of the motion is generated in a good program and is performed by a good motion controller PID parameters ...

Good resolution motion range is achieved by using a good feedback sensor that can accurately differentiate between the slightest change in its position and give the proper feedback ... that is also related to the motion smoothness that a motor can really produce ... that combination is has to be chosen carefully ...
There are a lot of simulators that are really doing great and there creators just used a very smart concept designs for there platforms and a well used common components that really did a great job ...

Motors used in motion simulators are endless types and shapes ... many types from many sources are used here even from the scrap yard .
the most common used around till now are DC wiper motors and DC worm gear motors big ones ...
SCN5 and SCN6 are used on a very good scale ... AC motors too are going good ...
but there are no projects till now that are using stepper motors, servo motors, BLDC motors " too expensive drivers for such motors " ...

Now If you still have questions just ask ... Or you find this post informative enough then go to the next step ... Have a look and understand the SimTools program here in the Tutorials section .

Accuracy & Repeatability!
I will NOT forget that!

Tom

Types and uses of hall effect sensors as a Feedback sensors ...

Types of the normal 10K pot ... see it in action .

I have a test unit with stepper and know of a couple testing Ac servos at the present, but we are keeping quite for now until we can show that it works and be able to write up how to do it too.

Nice information well done, The Jrks operate in the same way as an industrial pid controller does, they might be micro but they put out hell of a punch.


Copied from here - http://www.pololu.com/docs/0J38/1.c

Nice @eaorobbie ... yes keep it under cover please until it is chocked good ...

Can you/any one remember that there was a flow chart with ...
start > get in game value > get feedback value > .... something like that describing the basics

plus the first post needs a video that displays the test profile of SimTools just driving a motor
is it there somewhere ?
any thing like that may help
many thanks ...

is this any help? I ran a dirt3 benchmark and let the motors do the rest

Thanks @bsft for me it's more than enough ...

But for a new member it still can be little unknown I guess ... " please sir I want some more " Oliver Twist ...

let's just see what response gonna be ? hit me in the concept level .

I have not built anything yet but reading all I can. One thing I can not find is some sort of single line diagram.
something like.......computer>arduino(?)>motor controller(jrk)>motor.
Does that sound right? Does it have to be an arduino?
Any help is appreciated.
Thanks
Rick

Yes @rick surette that is right ... and It doesn't have to be arduino ... you have also the SimAxe and the jrk as motor controller that can handle motion control too ... here is the latest @bsft projects using JRKs ...

@rick surette : have a look at the Quick Starting guide: you will find some diagrams...

game plays,
simtools reads data from game via game plugin program
simtools sends data to control board,
control board with feedback moves motor/actuator to generate motion.

where is that ? do you mean the DIY tutorials ?

@abdo_tahan : no, the Quickstart Guide linked in my signature : http://www.xsimulator.net/simtools-quickstart/

Great! thank you very much.
Some more reading before I start.
Thanks you guy's
Rick

I guess One of the most important applications in balanced motion systems is the SEGWAY ...
unbalancing "controlling " the mechanical side of sensors ... gives you the motion required .

Original post updated ...

And extra information about motion control are here ...
http://www.ni.com/white-paper/3367/en/

Speedy,
Good read - lots of information.

Thanks,
Tom

Must agree with cthiggin as this is right up my alley. I am on the edge of my seat reading it all with great interest!
Really enjoying this community and the vast amount of knowledge amongst all the members.

To ALL a BIG thank you!

skip to the middle first ... then you'll repeat it endless .