Hexapod Spider Robot
issue 1

Hexapod Spider Robot

Monali Mahajan*, Harshal Rahangdale*, Aanchal Khode*, Pratiksha Puri*, Anuj giri*,Dr. Sachin Solanki
Student, Dept. of Information Technology, KDK College of Engineering, Nagpur, India, puripratiksha10798 @gmail.com


The objectives of the paper are to present the evaluation in area of legged locomotion system and it has ability to alert us from complex terror attack. Conventional wheel is famous in the industrial mobile robot because it is simple and easy to control. On the other hand, the leg robot is locomotion. The research paper describes four leg robot design. The leg material is made with fiber glass.

Keywords – Multi-leg robot, hexapod, design methodology


Multileg hexapod robot is programmable robot with four legs attached to the robot body. Legs are controlled degree of autonomy so that robot can move anywhere or within environment, to perform tasks hexapod robot are suitable for monitoring activities. It has features such as omnidirectional motion, it has good stability and fault tolerant locomotion. The coordinated moment control of multileg robot has been difficult problem in the field of robotic because robot needs to make quick response. In this work a new controller algorithm based on CPG-ZMP (Central pattern generator-zero moment point) is put forward in order to realise smooth gait planning and stability control at the same time. The algorithm has been applied on joints multileg robot, which greatly improves the stability of moment and the flexibility of gait generation and switch. The control strategy based on biological induction is a new control idea that has been gradually carried out in the multileg robot researchers in which the alternate rhythmic moment of each leg of the hexapod robot is the most common. The Wilson-COWAN neural oscillator controller for hexapod robot rhythmic locomotion control, which is known as weekly neural network that generate rhythmic moments in locomotion of multileg robot. The harmony motion of the leg from the other is controlled with four Wilson-Cowan neural oscillator. The period and amplitude of the CPG model are easy to control for generating various gaits but the real time of adjusting the model oscillation system and stability control need to further improve.




The oscillator model presented by Wilson and Cowan is shown in figure 2, which is composed of excitatory neuron u and inhibitory neuron v. A stable limit cycle is formed by the inter coupling of u and v.

Figure 2.


  1. Inhibitory Connection.
  2. The Robot Structure

The robot has four legs that have the same module for each leg. It has 12 joints. The robot size is approximately sm all, weight is near about 500 gm including Arduino kit and battery. the robot body frame is made from acrylic material.


In robotics, inverse kinematics is the mathematical process of calculating the variable joint parameters in robot, manipulator or animation character’s skeleton in a given position and orientation e.g. the hand of robot can typically be calculated directly using multiple applications of trigonometric formulas, a process known as forward kinematics. The reverse operation is more challenging

Representation of Inverse and Forward Kinematics

In robotics inverse kinematics makes use of the kinematic equations to determine the joint parameters that provide a desired position for each of the robot’s end effectors. Specification of the movement of a robot so that is end effectors achieve the desired task is known as motion planning. Inverse kinematics for walling the joins required to get the tip of the leg in a certain position relative to the body

Basic Trigonometry

To start we need to determine geometry of the leg and describe it using mathematical formulas.

To calculate diagonal of rectangle, we can use Pythagoras Theorem

To calculate one of the angles of the triangle for which we have the lengths of all sides, we can use the Law of Cosines: which gives us .

We have the angles, but they are unlikely to have to align with where our physical servomotors have their zero angles, and the direction and they turn. We have to add offsets to them and possibly reverse them. The easiest way to go about that is to set all our servers to zero and check where the end of the leg should be then.

Walking Algorithms

The way in which an animal or robot walk is called a gait, it tells us what order the legs are moved, how the body is balanced and how it moves forward.

When the robot walks, it has to keep its distance. There are to general step for doing that, and according to them, we divide the gaits into statically stable and dynamically stable. For statistically stable gaits it doesn’t matter how fast they are performed, or whether the robot is stopped in a middle of a step is stable at any movement, at all times. Animal and people use those gaits when they want to go slowly, or when they want to able to stop at any time. Dynamically stable gaits are much harder, as they have to perform at particular speed and cannot be interrupted at an arbitrary point most robot gaits are dynamically stable as they tend to be faster and more energy efficient E.g. “Trot Gait”.


The strolling stride potentially has numerous examples under the state of a smooth floor with the ZMP region as a strength measure. Usually, ZMP is utilized for dynamical strolling, yet for this situation, it has to start a few conditions to make the robot walk constantly with no falling head over heels or stumbling as in Figure4.

Figure 4

Design Considerations

  • The mechanical structure of robot body;
  • Leg architecture;
  • Max sizes;
  • Actuators and drive mechanisms;
  • Control architecture;
  • Power supply;
  • Walking gaits and speed;
  • Obstacle avoidance capability;
  • Payload;
  • Operation features;
  • Cost.

Why and When do we need Robot?

  • Robots work without break or the need to sleep or eat, allowing manufactures to streamline processes and improve output.
  • The world needs robots for an innumerable number of reasons, counting perilous employments and robotized fabricating.
  • Robots are utilized in jobs going from tidying up perilous waste and compound spills to incapacitating bombs.

Software and Hardware Specifications

  • Arduino
  • Servo Motors
  • Power Supply
  • ARDUINO IDE Software
  • Bluetooth connecting slot

Walking Locomotion

Multi Legged robots are based on insect locomotion. Numerous legs permit a few unique steps, regardless of whether a leg is harmed, making their developments increasingly helpful in robots shipping objects.

Figure 5 Walking Pattern

For the spider locomotion we will use two types of gait generation. Spider will move in any direction as well an on uneven surface.


In multileg spider development leg design are adopted by spider and the insects. The leg design has proven popular for number of different legged robot the mechanism consists of simple four legged

Kinematic representation
In creating robot to work in human condition ,human like strolling appears the most proper type of velocity as the robot needs to move around in a situation with obstacles and climb up and down stairs .the main advantage of the legged design are simplicity ,a simple interface and low cost .overall leg moment of spider is exact like spider


  1. umar Asif (2011), “kinematic Analysis of Periodic Continuous Gaits for a Bio Mimetic Walking Robot” IEEE International Symposium on Safety, Security and Rescue Robotics , pp 80-85
  2. William A. Lewinger , “A Hexapod Robot Modeled on the Stick Insect, Carausius morosus” International Conference on Advanced Robotics , PP20-23,Jun2011
  3. Ravi Kumar Mandava Research Scholar, “Forward and Inverse Kinematic based Full Body Gait Generation of Biped Robot” International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT) – 2016
  4. Mcmahon, T. A.; “Mechanics of Locomotion”, The Intl. Journal of Robotics Research, Vol. 3 No 2, Summer, (1984);
  5. Antonio Bento Filho1 , Paulo Faria S Amaral2 and Benedito G Miglio Pinto3 1 Mechanical Engineering Department, 2 Electrical Engineering Department, Federal University of Espirito Santo, 3 Automatica Tecnologia S/A, Vitoria, ES, Brazil “A Four Legged Walking Robot with Obstacle Overcoming Capabilities” (2010)

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