My 6 joint robot arm structure doesn't meet the requirements for a closed form solution (no 3 consecutive axes intersecting at a point or 3 parallel axes...).

What would be best method to adopt to get solution in 1ms or less? Estimation accuracy of 1mm. I'm assuming the computation is done on an average laptop Intel Core i3, 1.7GHz, 4GB RAM

  • 1
    $\begingroup$ So then what IS the robotic arm structure? Can you post drawings? $\endgroup$
    – Chuck
    Aug 22, 2015 at 12:15
  • $\begingroup$ An "average laptop" doesn't have a real time operating system. $\endgroup$ Aug 22, 2015 at 13:15
  • $\begingroup$ Wish I could post the arm structure! All I can share abt the arm is that it's serial chain, all revolute joints. $\endgroup$
    – vinjk
    Aug 23, 2015 at 10:07
  • $\begingroup$ How many joints in your arm? $\endgroup$
    – Ben
    Aug 23, 2015 at 12:44
  • $\begingroup$ @Ben six joints serially connected $\endgroup$
    – vinjk
    Aug 24, 2015 at 8:51

1 Answer 1


I don't believe 3 consecutive axes intersecting at a point rules out closed form solutions. Although i don't have a reference for this.

You should investigate OpenRave and ikfast. This will generate library independent optimized C++ code with closed form solutions for a wide variety of kinematic chains and IK types.

I found this paper that might be of interest to you:

Luo, R.C.; Tsung-Wei Lin; Yun-Hsuan Tsai, "Analytical inverse kinematic solution for modularized 7-DoF redundant manipulators with offsets at shoulder and wrist," in Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference on , vol., no., pp.516-521, 14-18 Sept. 2014

While it describes a 7 DOF arm, its shoulder and wrist joints don't intersect at a point. You might gain some insight from their formulation, or perhaps some of their references.

  • $\begingroup$ Thanks for directing me towards openrave. But I just can't get to install it on win 7. I installed it on Ubuntu 14.04. But unfortunately it crashes as soon as I open an example. Can it solve for general 6dof serial structure? Do you how he solves it using analytical method? Couldn't understand fully from the developer's thesis. $\endgroup$
    – vinjk
    Aug 24, 2015 at 8:48

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