hi,
here is the scenario:
there is a line/rope connected to a winch system. someone pulls the line and the winch lets out the line. but it resists the pulling of the rope. so there should be certain amount of force to pull the rope out.
and I want to be able to control the amount of force required to do so
I have no idea what to look for. could you please help me out?
p2rate:
hi,here is the scenario:
there is a line/rope connected to a winch system. someone pulls the line and the winch lets out the line. but it resists the pulling of the rope. so there should be certain amount of force to pull the rope out.
and I want to be able to control the amount of force required to do soI have no idea what to look for. could you please help me out?
Your scenario leaves out all information necessary to offer any help. Describe the winch and the rope and how hard you want someone to pull.
Does the winch have a brake? Can you add a roller to loop the rope around? Can you add an electric brake to the roller? Do you have a servo that can control the torque necessary to produce the force you need to resis the rope pull?
Or is this all just dreaming?
Paul
More concrete details are needed before any choice of mechanism can be meaningful I think.
Paul_KD7HB:
Your scenario leaves out all information necessary to offer any help. Describe the winch and the rope and how hard you want someone to pull.Does the winch have a brake? Can you add a roller to loop the rope around? Can you add an electric brake to the roller? Do you have a servo that can control the torque necessary to produce the force you need to resis the rope pull?
Or is this all just dreaming?
Paul
actually this is not a rope but a line. I am trying to build a paraglider simulator.
paraglider is controlled by pulling of two handles.
these handles are connected to the paraglider via light lines.
obviously you feel a resistance when you pull down the break.
the amount of this resistance increases as you pull the break more.
at the beginning the break pressure is almost neglectable.
the maximum break pressure could be something like 500 newton
the break travel length is something like 50 cm
as you release the break back up it should be retracted very quickly avoiding of the break line dangling around
I did not know that a winch could have breaks. I do not know what kind of equipment I need and I have not bought any. I am open to any suggestions.(the cheaper the better :D)
I do not need precise instructions but more of a overall guideline. I was thinking perhaps to use a DC or step motor to constantly pull in the rope by a certain speed. then I would have to force to make the motor turn the other way by pulling the line out
I presume you mean "brake" rather than "break" - there is a big difference.
...R
With a DC motor the current determines the torque, so it sounds like you need a four-quadrant motor
controller with torque-control option.
Stepper motor is utterly unsuitable.
p2rate:
hi,here is the scenario:
there is a line/rope connected to a winch system. someone pulls the line and the winch lets out the line. but it resists the pulling of the rope. so there should be certain amount of force to pull the rope out.
and I want to be able to control the amount of force required to do soI have no idea what to look for. could you please help me out?
Some people try to complicate something beyond all comprehension.
Go to your local hardware store and look at their selection of coil springs. Pick one that has the length of movement and the strength you need and use one for each line. OR if there are only two lines, Use one spring that is supported in the middle and attach a line to each end of the spring.
Good Grief!!!
Paul
Robin2:
I presume you mean "brake" rather than "break" - there is a big difference....R
yes you are right, my bad
MarkT:
With a DC motor the current determines the torque, so it sounds like you need a four-quadrant motor
controller with torque-control option.Stepper motor is utterly unsuitable.
is it alright to force the motor turn the other way? isn't it harmful to the motor?
is there a better way to do it?
Paul_KD7HB:
Some people try to complicate something beyond all comprehension.Go to your local hardware store and look at their selection of coil springs. Pick one that has the length of movement and the strength you need and use one for each line. OR if there are only two lines, Use one spring that is supported in the middle and attach a line to each end of the spring.
Good Grief!!!
Paul
thank you for your insight, but it is not as simple as you think
after pulling the brake too much the wing stalls and break pressure drops to almost zero. after this point the reaction of the brake becomes totally different. releasing it back up the brake pressure is still soft. there is a lot more to this
p2rate:
is it alright to force the motor turn the other way? isn't it harmful to the motor?
That depends on the motor. If you want to force it backwards then you need a motor that can comfortably survive with the stall current flowing in it while it is stationary. Some motors are designed for that.
Another possibility is that you have a motor driver that limits the current to an amount that the motor can survive while stationary. However that may not be so simple to arrange. Many drivers with over-current protection just shut down - which would probably not be appropriate for your project.
...R
after pulling the brake too much the wing stalls and break pressure drops to almost zero. after this point the reaction of the brake becomes totally different. releasing it back up the brake pressure is still soft. there is a lot more to this
Then you need to look at industrial type servo motors and controllers for them. Also need to know how far the line has been pulled.
Paul
I think it would help if the OP were to provide a better description of the project he is trying to create. I find it very hard to visualise the system described in Reply #3.
For example is the "brake" thing an "air brake"?
A diagram would be a big help.
thanks to you all
I have been asking around. I knew about a very similar project and I contacted the designer.
he said they have been using hydraulic motor in their project. I am going to have a meeting with the guy and will share as I get more info.
from what I gathered on the phone and my research on the web the hydraulic motor is powered by a compressed fluid. therefore you would need a compressor for this project too. the torque of the motor is proportional to the difference of pressure of input and output fluid. speed of rotation is proportional to the amount of fluid that is passed through.
in their setup they have a valve that is operated manually to control the aforementioned behavior. so using an electronic valve we can control it by Arduino
Almost all liquids are NON-compressible by definition. A pump, usually a gear pump is used to force the liquid to move. The hydraulic motor is a gear pump as well, but being moved by the liquid force.
All the hydraulic systems also need an accumulator with air in it to smooth out the sudden surge in pressure that might over load the system.
Look into a needle valve to control the pressure, not a ball valve or similar. Needle valves can be designed to be nearly linear with rotation of the screw on the needle. That is where you would put the motor.
Paul