Goal Directed Design of Manipulators Based on Task Descriptions

Sarosh Patel
Tarek Sobh



Inverse Kinematics


Publications & Presentations


    Computing the optimal geometric structure of manipulators is one of the most intricate problems in contemporary robot kinematics. Robotic manipulators are designed and built to perform certain predetermined tasks. It is therefore important to incorporate such task requirements during the design and synthesis of the robotic manipulators. Such task requirements and performance constraints can be specified in terms of the required end-effector positions, orientations along the task trajectory. In this work, we define, develop and test a methodology that can generate optimal manipulator geometric structures based on the task requirements. Another objective of this work is to guarantee task performance under user defined joint constraints. Using this methodology, task-based optimal manipulator structures can be generated that guarantee task performance under set operating constraints.

   The rapid growth in manufacturing technologies has increased the need for design and development of optimal machinery. No longer is the emphasis on machinery that works but on machinery that works faster, consumes less power, and is more functional. Designing optimal machinery and processes has become a necessary criterion across all engineering disciplines. The availability of computing power allows us to design and evaluate multiple structures based on user defined criteria and select the best. In this work we propose a method for designing optimal robotic manipulator structures.
     What is the best manipulator configuration for soldering electronic components? What should be the ideal manipulator structure for a painting job? What is optimal manipulator configuration for a material handling job? Robotics researchers over the years have tried to find answers to these questions. But in this case plenty is the problem; there is no unique solution or definite answer to these questions. Instead, in most cases there can be infinite answers to any of the above questions. Equations describing the kinematic behavior of serial manipulators are highly nonlinear with no closed solutions. The difficulty in most cases lies not in finding a solution, but finding the 'best' solution out of the numerous possible solutions, or in other words, an optimal solution.

     The research area of robotic manipulator design can be broadly classified into general purpose designs and task specific designs. Even though general purpose manipulators are commonplace, they do not guarantee optimal task execution. Because industrial robotic manipulators perform a given set of tasks repeatedly, task-specific or task-optimized manipulator designs are preferred for industrial applications.  The goal of this work is to develop a methodology that can serve as a simple and fast tool for synthesis of robotic manipulators based on task descriptions. The proposed methodology allows a user to enter the task point descriptions and joint constraints, and generates the optimal manipulator geometry for the specific task.