Design and Development of a Redundant Manipulator Arm



Aims and Objectives:

The central idea is this project is to use a Redundant Manipulator to work around obstacles. It is expected that the manipulator would successfully demonstrate Path Planning and Obstacle Avoidance in its way towards the goal as shown in the following animated gif.

Plants which require maintenance and inspection of sites which are inhospitable to human beings due to number of reasons like, high temperature, presence of toxic or radioactive substances, demand such manipulators. Redundancy is required for Obstacle Avoidance (A manipulator is said to have redundant links, if it has degrees of freedom more than required to reach a point. In the case of parallel plane and serial manipulators, a manipulator is said to have redundant links if it has more than 2 degrees of freedom).

The situation is complicated as many of the inspection sites are difficult to access manually (as the workspace may be very congested) as well as by mobile robots (as the terrain may not be even). In such a scenario, the inspection sites can be accessed in a serpentine fashion.

The present project is intended to meet such demands of a complicated environment, by harnessing the potential of redundant manipulators to move in a serpentine fashion.


A robot manipulator having more degrees of freedom than essential for accessing a point in space is called a redundant manipulator. Such redundancy helps in obstacle avoidance, singularity avoidance, workspace enhancement, performance optimization and improvement in reliability leading to safer operational situations. The redundancy will be utilized for reaching and dexterous maneuvering at locations that are difficult to reach, but nevertheless require periodic maintenance. Path Planning and Obstacle Avoidance strategies are required. Subsequently various control schemes will be designed for the system and comparatively evaluated in order to finalize the most suitable strategy.This entire exercise is expected to lead to a systematic methodology to design a redundant manipulator for any workcell that may involve inaccessible locations.

Steps Involved:

Current Status:

Till now we have completed the theoretical aspects, like Path Planning and Mechanical Designing. However graphical testing of the Path Planner is still going on. Attempt to make it as general as possible, i.e. independent of workspace, is going on. Manufacturing of the components has started. This project is expected to complete by February end. If successfully completed we will go for its publication. Meanwhile the page will be updated from time to time till the end of the project.

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