Reason behind Robotic Arm in Robotics Environment Simulator vibration

[Zainab94]

I have managed to design my robotic arm using LabVIEW's Robot Model Simulation Builder and have included my robot in the Robotics Environment Simulator and I'm controlling my arm in the simulation by manually controlling the servo sensors on each joint, I noticed that my arm vibrates a lot when it should be standing still in it's position. I need to fix that, what can I do to fix this issue. I have attached a screen shot of my program's front panel. I can show my program if that would help with finding the issue. 

PS. I have added the actual masses of each link in the robot model, I'm thinking that it could be an issue with the dynamic parameters of the model that i could be missing. 

[Alex-C]

Hi,

Providing the program could be helpful to start narrowing down what could be causing the issue. 

There could be an issue that your equipment is accounting for small changes and is constantly trying to put the arm at a certain position, instead of putting it in that position once and leaving it there.

Alex C.

National Instruments

[Zainab94]

Thank you for replying. 

I did what you advised me to do, by sending the joint position command once. I did that by adding a feedback node and comparing constantly between the last command and the new command, if they were not equal then the joint angles will be updated. however, that did not solve my problem. I noticed that the robotic arm was falling down in my simulator due to gravity and so when i change the gravity acceleration in the environment properties option, the robot stays still and responds to my commands well without vibrating. my robotic arm is not heavy, and it does fall down in the real world too when it's not connected to power, but when it is powered it tries to stay in its position and the error correcting is not noticeable. so I noticed that my simulation gets better when the simulator step size is really low, because that means it's correcting the error very fast and hence the error is less noticeable. I have attached my original code after only reducing the step size of the simulation and I have also attached the modified version with the feedback node without changing the step size. 

[Kodester]

Hi Zaina,

Are you programming this based off an example? I'm asking because it would be nice to have a simplest case to work on

[Zainab94]

Hi Kodester, 

Yes I am actually. I sorted out the problem by reducing the simulation's step size. 

[51huaajia]

Hi，I  am new leaner of labview and  doing the similar work met with the same situation，it hit me a lot，have you solved your problem？could you share your latest program？

[51huaajia]

the front  program you have provided lost some sub-VIS such as 'generate arm kinematic model' and   ‘posture to transform’.