Hi ,
I am trying to use the PinJoint for simplicity and avoid other custom joints. But have some doubts on it.
1. Is it possible to include any function into it, like the linear function for transformation found in other joints. As as shown in the fig attached, I want my joint to rotate in clock wise direction , but by default its in the opposite way.
2. Secondly, is it possible to set the starting point 0 deg from left to 90 deg position as shown in figure.
3. Is it possible to change the axis of rotation from Z to any other axis like X or Y. Or is it only permitted in Z axis.
Looking forward to any reply,
Nithin
Doubts on PinJoints
Re: Doubts on PinJoints
Your point 1 is irrelevant to PinJoint. The functions in CustomJoint are inside a SpatialTransform which allows you to couple spatial (6dof) kinematics to between 1 and 6 internal coordinates.
A PinJoint is not arbitrary and is defined to rotate about the respective Z axis of the parent and child frames. That is, the bodies connected by the PinJoint are aligned so the z-axes of the joint frames are coincident and there is free movement about that axis. There is no need to define any additional axes or functions.
For any Joint in OpenSim you have total control on how the joint frames are located and oriented in the child and parent bodies (e.g. <location>, <orientation> and <location_in_parent>, <orientation_in_parent> fields. For location it is the x,y,z coordinates in the (child/parent) Body frame in meters. For orientation it is the XYZ body fixed (in child/parent) Euler angle sequence in radians.
You can edit the properties and visualize the joint frames (axes) in the GUI. You select the joint of interest in the navigator and right click to see the options to toggle (view) child and parent frames.
A PinJoint is not arbitrary and is defined to rotate about the respective Z axis of the parent and child frames. That is, the bodies connected by the PinJoint are aligned so the z-axes of the joint frames are coincident and there is free movement about that axis. There is no need to define any additional axes or functions.
For any Joint in OpenSim you have total control on how the joint frames are located and oriented in the child and parent bodies (e.g. <location>, <orientation> and <location_in_parent>, <orientation_in_parent> fields. For location it is the x,y,z coordinates in the (child/parent) Body frame in meters. For orientation it is the XYZ body fixed (in child/parent) Euler angle sequence in radians.
You can edit the properties and visualize the joint frames (axes) in the GUI. You select the joint of interest in the navigator and right click to see the options to toggle (view) child and parent frames.
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Nithin Kurup
- Posts: 149
- Joined: Sat Jan 18, 2014 5:13 am
Re: Doubts on PinJoints
Dear Ajay,
Thank you so much for your detailed explanation. I changed the orientation of the parent-child axes in the GUI and it came out perfectly .
Thanking you again,
Nithin
Thank you so much for your detailed explanation. I changed the orientation of the parent-child axes in the GUI and it came out perfectly .
Thanking you again,
Nithin