simtk.org

Hi, everyone
I create a gait model with 6 DOF (3 rotations and 3 translations) of knee joint for simulate gait cycle. When I use this model for simulation, I have a hard time to setting the RRA setting files.
I firstly add the code similar to the model2354 example as below:

for "RRA_actuator.xml" file
<CoordinateActuator name="knee_tx_r">
<isDisabled> false </isDisabled>
<!--Minimum allowed value for control signal. Used primarily when solving
for control values-->
<min_control> -infinity </min_control>
<!--Maximum allowed value for control signal. Used primarily when solving
for control values-->
<max_control> infinity </max_control>
<coordinate> knee_tx_r </coordinate>
<optimal_force> 300.00000000000000000000 </optimal_force>
</CoordinateActuator>

for "RRA_ControlConstraint.xml"
<ControlLinear name="knee_tx_r.excitation">
<is_model_control> true </is_model_control>
<extrapolate> true </extrapolate>
<default_min> -20.00000000000000000000 </default_min>
<default_max> 20.00000000000000000000 </default_max>
<filter_on> false </filter_on>
<use_steps> false </use_steps>
<x_nodes/>
<min_nodes/>
<max_nodes/>
<kp> 100.00000000000000000000 </kp>
<kv> 20.00000000000000000000 </kv>
</ControlLinear>

for "RRA_task.xml"
<rdCMC_Joint name="knee_tx_r">
<wrt_body> -1 </wrt_body>
<express_body> -1 </express_body>
<on> true </on>
<active> true false false </active>
<weight> 2.0e1 </weight>
<kp> 100.0 </kp>
<kv> 20.0 </kv>
<coordinate> knee_extend_r </coordinate>
</rdCMC_Joint>

the same code was added for knee_ty and knee_tz, however, the RRA ran strange, the tibia try to go upward all the time and it is totally not like gait any more.

so does anyone know what is wrong with my code or how to set translation coordinate in RRA ?
I appreciate any help!