DESIGN AND FABRICATION OF RECONFIGURABLE SPIDER ROBOT

Project Title

DESIGN AND FABRICATION OF RECONFIGURABLE SPIDER ROBOT

Project Area of Specialization RoboticsProject Summary

This project is to design and fabrication of reconfigurable spider robot. This is Bio-Inspired by Moracann Flic Flac Spider, is a rare species of huntsman spider which can crawl and roll by using its legs. This spider is found in sand dunes of the Erg Chebbi desert in Morocco. The reconfiguration design has been studied and applied in robotics since the early 1980s. The design of Reconfigurability is a valuable after implementation of reconfigurability in different practical designs. The design and unique features of reconfigurable hexapod robot, with rolling and crawling locomotion abilities are presented in this project. In crawling configuration, robot locomotion is excellent for rough, inclining slope and uneven surfaces (maximum 4cm) like Small Stones, grass. In rolling configuration is for higher speed and is more energy-efficient over a smooth surface and decline slope. The mobile robots are used in numerous applications in which includes search, reconnaissance and surveillance missions. This robot also has capability to perform quick rescue operations in disasters.

Project Objectives

• To make 3D CAD Design of Robot
• To interface sensors and motors with microcontroller (STM32F303VC) and simulate it.
• Design and Fabrication of Hardware.
• Implementation of Autonomous tripod gait motion in the legs.
• To achieve Shape Shifting Locomotion Capabilities.
• To achieve Recovery behavior Capabilities.

Project Implementation Method

• First, we do literature review and make its conceptual design.
• Then, we selected the components of our project.
• On the basis of components selection, we make it 3D CAD Design.
• We interface the sensors (sharp distance sensor, Bluetooth module) and servo motor (MG-90) with Microcontroller (STM32F3 Discovery Kit).
• We configured the built in MEMS motion sensor (3D Gyro, L3GD20 in STM32F3) which is used for autonomously take decision either rolling or Crawling and recovery behavior i-e robot can change its state from unknown position to standing gait position.
• We selected the PETG material for 3D printing of the robot body parts.
• Then we make 3D printed prototype of one leg and assembled it with servo motors for testing.
• Then we will make PCB design on proteus software.as well as make hardware.
• Then we will 3D print the complete design of robot.
• Then we will assemble complete hardware (Robot Body, Sensors, Motors, Microcontroller, Lithium Ion Cells).
• After that we will do testing of complete hexapod robot for crawling, rolling and recovery behavior.

Benefits of the Project

• Mobile robots capable of traversing rough terrains are highly desired for numerous applications including search, reconnaissance and surveillance missions.
• Robot is used to perform quick rescue operation in disasters. 
• Hexapod is used to test biological theories about insect locomotion, motor controls and neuro biology.
• This is used in volcanic exploration, detection of antipersonnel landmines, sample collection, search for life.
• The most of above-mentioned task are hazardous and are usually accompanied by harsh environment, not compatible with human operations.

Technical Details of Final Deliverable

• This is hexapod (six legged) reconfigurable robot to perform crawling over rough surface while rolling over a smooth surface and decline slope.
• The dimension of robot while crawling is 368mmx360mmx210mm (LxWxH) and diameter of the robot while rolling is 200mm.
• The body of robot contains control unit, power supply and sensing unit.
• The control unit of the robot is STM32F303VC Discovery Board which has following specifications:
  • 256 Kbytes of Flash memory
  • 48 Kbytes of RAM in an LQFP100 package
  • It is used to generate PWM for the servo motors. We use 18 servo motors in this project.
  • Board power supply: 3 V or 5 V supply voltage
  • L3GD20, ST MEMS motion sensor, 3-axis digital output gyroscope is used for identification of orientation of the robot.
  • LSM303DLHC, ST MEMS system-in-package featuring a 3D digital linear acceleration sensor and a 3D digital magnetic sensor  
• Power supply of robot is consisting of four rechargeable lithium ion cells (3.7V, 1800mAh).
• The direction of robot is controlled by remote (Bluetooth module HC-05).
• Three IR sharp distance sensor(2Y0A02) are used one on front and two on side of robot, for obstacle avoidance and safety of robot from collisions.  
• The six legs of the robot are the multi-jointed, semi-circular structures with three DOF. Each leg consists of three servo motors.
• The servo motor is used in this project is MG 90 which has:
  • Tiny and lightweight with high output power.
  • Operating voltage: 4.8 V -6.0 v
  • Stall torque: 1.8 kgf·cm (4.8V ) 2.2 kgf·cm (6 V)
  • Dimension: 22.5 x 12 x 35.5
  • Weight: 13.4 g
  • It can rotate approximately 180 degrees.
  • Metal gears for added strength and durability.
• The whole body of the robot is fabricated using PETG (Polyethylene Terephthalate Glycol) material by 3D printing. This material is Extremely durable and flexible used for high impact or high stress parts. This material is easy to print as compared to ABS material. It can resist temperature up to 80oC and it is chemically resistant
• Robot take decision autonomously either rolling or crawling according to surface by using MEMS motion sensor(L3GD20).
• Robot also have capability to change its state from unknown to standing gait motion by using MEMS motion sensor (L3GD20).

Final Deliverable of the Project HW/SW integrated systemCore Industry OthersOther Industries Health , Security Core Technology RoboticsOther Technologies OthersSustainable Development Goals Good Health and Well-Being for People, Decent Work and Economic GrowthRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	24370
Microcontroller (STM32F303VC Discovery Kit)	Equipment	1	3600	3600
Servo Motors (MG-90)	Equipment	18	300	5400
IR Sharp Distance Sensor (2Y0A02)	Equipment	3	900	2700
3D Printing	Equipment	1	10000	10000
Bluetooth Module(HC-05)	Equipment	2	280	560
Lithium ion Cells (3.7V, 1800mAh)	Equipment	4	190	760
PCB Designing	Equipment	1	400	400
Wires	Equipment	25	4	100
Testing	Miscellaneous	1	850	850