Design and Development of Multi DOF Robotic Manipulator
The use of robotic manipulators is essential to modern industry for tasks involving human health and safety risks. Industries in Pakistan pay high costs not just for importing Robotic Manipulators but also for their aftersales services and maintenan
2025-06-28 16:26:18 - Adil Khan
Design and Development of Multi DOF Robotic Manipulator
Project Area of Specialization RoboticsProject SummaryThe use of robotic manipulators is essential to modern industry for tasks involving human health and safety risks. Industries in Pakistan pay high costs not just for importing Robotic Manipulators but also for their aftersales services and maintenance. The aim of the project proposed in this report is to indigenously design industrial manipulators to facilitate local industries in lightweight robotic applications such as painting, welding, pick, and place, etc., The project employs mechanical design techniques for CAD modeling, manufacturing, and assembly of robot. For software integration, motors are run in the joint assembly using the EPOS microcontrollers and driver. Twin-CAT networking in CANBUS configuration is proposed by the report to implement the control of the robot. The study shows the completed design of links and joints and the result of manufacturing, assembly, and testing of joints 1, 3, and 4, base and links 1 and 2. It also suggests the implementation of inverse kinematics of the robot using Twin-CAT software. The scope of the project is to provide a base for the finished product of an industrial collaborative manipulator. With the advent of the 4th industrial revolution, the project can play an important role in Pakistan’s industrial automation. It will be a standard-based, affordable product with flexible automation capabilities.
Project ObjectivesOur project aims at the design, manufacturing, and control of the multi-DOF Robot. Following are the topics addressed in the project:
- To design a test bench for motors and harmonic drive testing.
- To design 1-7 joints of the robot with proper torque fulfilments
- To design the base of the robot with a load capacity of 50kg
- To design links for the robot.
- To explore and implement manufacturing techniques for joint, link, and base manufacturing
Robotic manipulators are made with different design philosophies, which may differ in driving systems e.g., DC Motors, BLDC Motors (In-runners, Out-runners, Framed, Frameless), AC Servos, etc., Links e.g., Cylindrical Links, Rectangular Links, Complex Profiled Links, etc. They also differ in their base designs e.g.; the robot’s first joint is placed vertically or horizontally. Each design philosophy suits a different purpose of use. Over the period of time, HCR Lab evaluated, tested, and experimented with multiple types of technologies incorporating different design philosophies e.g., 5 DOF Robotic Manipulator was made with rectangular links, in-runner & out-runner motors with Nano-Tech motor controllers. With that experience, 7 DOF Robot was decided to be made with Out-Runner motors with an open Harmonic Drive gear system.
Joints are the core components of the Robot’s structure. They are desired to be compact, rugged, require low maintenance, and lightweight. The tradeoff between them depends upon the subjective requirement. The requirement of a 7 DOF Robotic Manipulator is to lift weights in industries, run continuously for longer periods of time, and consume less power. Therefore, the design process was long and repetitive. The Joint’s design evolved over a couple of years to the date where it has been frozen. There are 7 Joints in the robot, all following the same design philosophy.
The main parts of the design methodology covered:
- CAD design
- Assembly verification through prototyping
- Material selection
- Stress analysis
- Manufacturing
- Assembly
- Testing of joints
- Inverse Kinematics
- EtherCAT integration
A multi-degree of freedom robotic manipulator has vast applications. These robots support flexible automation and provide the user the ability to interact with the robot for teaching purposes. They are widely used in the industry for painting, welding, and pick and place applications along with their use in labs and educational institutions. However, developing such a robot in the limited resources available in Pakistan has been a challenge. As more local industries desire to move towards automation, it is not possible for each one of them to do so because of financial challenges. Robots that are imported from abroad are costly and are hardly affordable for local manufacturers. Thus one of the goals of the Human-centered Robotics Lab is to develop multi-degrees of freedom robotic manipulators suitable for Pakistani Industries.
Technical Details of Final DeliverableThe project “Multi-DOF Robotic Manipulator” covers the design and development of an industrial robot. It is designed as an industrial manipulator and is hoped to reach the final version of a collaborative robot after design iterations. The main deliverables of our final year project in contribution to the wider horizon of collaborative robots are as follows.
- Mechanical design of up to four joints of the robot using out-runner BLDC motors and harmonic drives.
- Joint design optimization and mechanical fault reduction through CAD simulations, prototyping, assembly assessments, and hardware testing.
- Joint manufacturing through material selection and exploration of the optimal manufacturing process. Joint fabrication considers local constraints, assembly, and testing.
- Link design considers the solvability, agility, flexibility, and load-bearing capacity of the robot. CAD design and simulations of various link designs and selection of the best design.
- Link manufacturing up to link number 3, process exploration in local scenario. Manufacturing challenges, and design trade-offs.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 69385 | |||
| Aluminium 6061-T6 Material for Fabrication | Equipment | 7 | 1425 | 9975 |
| Link-3 Fabrication | Equipment | 1 | 19000 | 19000 |
| SKF Lubricator | Equipment | 1 | 950 | 950 |
| Bolts & Screws | Equipment | 171 | 10 | 1710 |
| Manufactruing Shaft Joint-3 | Equipment | 1 | 5200 | 5200 |
| CRBH 5013 Cross Roller Bearings | Equipment | 1 | 2500 | 2500 |
| 6912, 6906 Bearings | Equipment | 2 | 1075 | 2150 |
| 4209 Bearing | Equipment | 1 | 2000 | 2000 |
| Link-2 Manufactruing | Equipment | 1 | 8000 | 8000 |
| Aluminum Material | Equipment | 7 | 1300 | 9100 |
| NTN 60/22 Bearing | Equipment | 1 | 800 | 800 |
| Base Joint Manufactruing | Equipment | 1 | 4000 | 4000 |
| 3D Printed Parts | Equipment | 2 | 2000 | 4000 |