calc_inverse_kinematics does not return valid joints for a legitimate xyz

[zainabalasadi]

I am attempting to use solve_ik_head_down() as written in the machine vision object pickup example here. It seems as though calc_inverse_kinematics() is failing to return joint angles for valid xyz cartesian positions. Below is my code:

"""
Move Eva to the given position. 
position: Catersian position, with respect to the robot's origin (in metres)
angle: Angular rotation of axis 6 in degrees
"""
def go_to_position(self, position, angle):
   // solve_ik_head_down is as in the link above
   success_ik, joints_ik = self.solve_ik_head_down(self.get_current_pos(), angle, position) 

   if 'success' in success_ik:
      with self.__eva.lock():
         self.__eva.control_go_to(joints_ik)
         print('Performed move to joint angles ', joints_ik)
         self.set_current_pos(joints_ik)
   elif 'error' in success_ik:
      print('Cannot perform move, error: ', success_ik)
   else:
      print('Attempting to go to joints: ', joints_ik)

I call go_to_position with the following values:

position is x = 0.1, y = 0.0, z = 0.0
angle is 0
self.get_current_pos() is [0.057526037, 0.7658633, -1.9867575, 0.026749607, -1.732109, -0.011505207]

I receive the following JSON message instead of the error format I expect as outlined in the docs. The lack of error messages makes it difficult to understand what is happening.

// format I get
{
  "ik": {
    "joints": [0, 0, 0, 0, 0, 0],
    "result": "ik"
  }
}

// format in docs for errors
{
  "ik": {
    "result": "error",
    "error": MOTION_ERROR
  }
}

Carrying out a calc_nudge() with the same parameters returns valid joints, although again, no error message is displayed when it fails (it just outputs [0, 0, 0, 0, 0, 0], different from what is specified in the docs.

I am using evasdk version 4.1.0. Any help on why calc_inverse_kinematics is not outputting valid joint angles for valid xyz positions would be appreciated.

[LouisBrunner]

Hi @zainabalasadi,

Thank you for your report, could you confirm the Software version of your Eva? (available on your Config page in Choreograph)

[zainabalasadi]

Hi @LouisBrunner, Eva is running on version 3.2.0