# I need help

hi
I want to give a motion to pedal in bike3d in curve profile, but i dont know how?
I try by AnyFunIntPol, but I have very error, i do this:
[SIZE=3]AnyRefNode[/SIZE] RPedal = {
[SIZE=3]AnyFunInterpol[/SIZE] RPedalLength = {
Type = Bspline;
FileName = “elips2.txt”;
};
sRel= elips2(t);
};
thanks

Hi,

‘sRel’ value in an AnyRefNode should be constant value.

Best regards,
Moonki

thanks moonki
I realy need to know how can i get complex curve for pedaling in bike?
please help me how do i get one value from text file matrix and choose it respect to time?

Hi

Moonki is right sRel needs to be a constant otherwise this would be equivalent to having a deformable segment.

So my understanding from you scriupt is that you would like to make the pedal arm change its length as a function of time.

Here is a sketch on how to do this:

AnySeg Shaft ={
AnyRefNode Crank ={sRel={0,0,0};}
Mass=…
Jii=…
};

AnySeg Pedal ={
AnyRefNode pedal ={sRel={0,0,0};}
Mass=…
Jii=…
};

AnyPrismaticJoint Jnt ={

Axis=x?;
AnyRefFrame &ref=.Crank;
AnyRefFrame &ref=.Pedal;

};

AnyKinEqInterPolDriver ={

Type = Bspline;
FileName = “elips2.txt”;
AnyPrismaticJoint &Ref=.Jnt
};

So there is a new segment for the pedal and this is driven along a prismatic joint .

Best regards
Søren

hi Toerholm
thanks for good answer, thats very bestway to solve my problem

i do that way to creat a curve but unfortunately ankle sprained while turning around crank, please help me how can i prevent that problem?

Hi

From your desription it is not clear to me what goes wrong with your model. Please add more details on what happend and how your model looks like.

Best regards
Søren

hi
thanks for your attention
in fact , my model is compistion of a wheelchair and a trike,by way of explanation human model push the wheel and by motion of wheel, crank will turn and it make the feet to move by turning the crank. two main problem occure, one of that is:1- I described a seg to creat a movable pedal as same as you suggested before, but after definig joints and driver and runnig that, ankle sprain while pedaling, i defined a driver to control hip abduction but nonetheless hip abducted, 2- the other problem is: when i ran the inverse dinamic after 0.2 second arm and hand muscle solver destroyed beacuse hand pushed excessively, and give error massage is:

question:
1- how can i prevent ankle sprain while pedaling?
2- how can i push rims repeatedly in desired number?
i defined a node on a wheel and creat a joint between palm and the node.
[SIZE=3]AnyFolder[/SIZE] Joints = {
[SIZE=3]AnySphericalJoint[/SIZE] HandRimRight = {
[SIZE=3]AnyRefNode[/SIZE] &Palm = Main.HumanModel.BodyModel.Right.ShoulderArm.Seg.Hand.PalmJoint;
[SIZE=3]AnyRefNode[/SIZE] &Rim = Main.MyBike.EnvironmentModel.RearWheel1.Pushrim1;
};
[SIZE=3]AnySphericalJoint[/SIZE] HandRimLeft = {
[SIZE=3]AnyRefNode[/SIZE] &Palm = Main.HumanModel.BodyModel.Left.ShoulderArm.Seg.Hand.PalmJoint;
[SIZE=3]AnyRefNode[/SIZE] &Rim = Main.MyBike.EnvironmentModel.RearWheel2.Pushrim2;
};
when hand extended excessively, solver broke down, and give this massage:
[SIZE=1][SIZE=1]ERROR(OBJ.MCH.MUS4)[/SIZE] : [SIZE=1]C:/U…s/PC1/A…a/R…g/A…y/A…x/A…0/A…n/E…s/M…y/MyBike.main.any[/SIZE] : [SIZE=1]MyStudy.InverseDynamics[/SIZE] : Muscle recruitment solver : maximum number of setbacks occured

if i want to repeat pushing form first point, it is difficult to use c3d file e.g wheelchairrancho , beacuse i want to use two hands and my model is diffirent. please help me.
[/SIZE]

Hi

I am sorry but it is still not 100% clear to me how the model looks like, here are some answers nevertheless, but please upload the model this will help us understand the problem.

1: By ankle sprain i assume that you mean you get excessive rotations in the ankle. This is a matter of the drivers… in the bycycle model of the repository we have a driver for the crank and a driver for the ankle joint, plus some extra drivers to keep the leg in place. I think your problem might be the ankle driver which needs to be altered, if you have taken over the driver from the bicycle model it migth need adjustments to the variables.

2: To do a push motion on wheelchair rims repeatedly would normally require you to have motion capture data to drive the model with. It is also possible to dream up the motion by parameterizing it but this is a difficult taks. Alternatively consider to only model the push phase.

Best regards
Søren