UR5e: How to calculate wrench at a virtual fixed point in real time?

Technical Questions URScript
1

Hey,

I have defined a fixed point in the base coordinate system. When dragging the TCP to maintain spherical motion, how can I compute the wrench at the fixed point in real time?

I know how to get wrench at flange：

def get_flange_wrench():
local ft = get_tcp_force()
local t_end_base = pose_trans(get_target_tcp_pose(), pose_inv(get_tcp_offset()))
local current_rot_in_tool = pose_inv(p[0, 0, 0, t_end_base[3], t_end_base[4], t_end_base[5]])
local f = pose_trans(current_rot_in_tool, p[ft[0], ft[1], ft[2], 0, 0, 0])
local t = pose_trans(current_rot_in_tool, p[ft[3], ft[4], ft[5], 0, 0, 0])
return [f[0], f[1], f[2], t[0], t[1], t[2]]
end

My approach :

tcp_offset = [135.76，135.76，126.51，0.0146，0.0437，-2.3713]  # just show my tcp offset
fixed_point = pose_trans(get_actual_tcp_pose(),p[0,0,0.3,0,0,0])

while True:
  wrench_at_flange = get_flange_wrench()
  current_flange_to_fixed_point = pose_trans(pose_inv(get_actual_tool_flange_pose()), fixed_point)
  wrench_at_fixed_point = wrench_trans(current_flange_to_fixed_point,    wrench_at_flange)

  #Make the robot move (Pseudocode)
  speedl(vel, a = 5, t = get_steptime())

end

Is my approach correct? I’m not entirely sure.

Thanks