Fundamentals of Inverse Kinematics Using Scara Robot

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Fundamentals of Inverse Kinematics Using Scara Robot Overview of SCARA Bot: The 2 Degree of freedom (DOF) Selective Compliance Articulate Robotic Arm (SCARA) (Selective Compliance Articulated Robot

1 Fundamentals of Inverse Kinematics Using Scara Robot Overview of SCARA Bot: The 2 Degree of freedom (DOF) Selective Compliance Articulate Robotic Arm (SCARA) (Selective Compliance Articulated Robot Arm) is a simplified model of a robotic arm ideally suited to introduce concepts of forward and inverse kinematics, mechanical design and motion control. In this project the student will learn to determine the requisite equations and subsequently position the robot tip in a plane from one desired point to another, with precision. This project is meant for anyone who wants to: Learn motion fundamentals. Learn forward and inverse kinematics. Learn design of mechanical systems. After you complete this project, you can explore the field of robotics and/or mechatronics.

2 What you will learn? In this project, you will learn: Mechanical modelling. Speed profile generation. Forward kinematics Inverse kinematics. Path generation. How to work on a bare metal system. However, this project does not cover the following: Higher order parametric equation based path generation. Driver development for hardware devices. Motor driver interfacing Prerequisites Before taking the project, you must have knowledge on the following topics of C language. You can obtain better understanding on the topics by referring the given links: Working of stepper motors Kinematics Basic Calculus and its discretization Industry Applications SCARA robots are used for a variety of general-purpose applications requiring fast, repeatable and articulate point-to-point movements such as: Palletizing, De-Palletizing, Machine loading or Unloading and Assembly

3 Hardware and Software Requirement: SCARA BOT Apparatus with controller Pen mechanism Power Supply Hardware Accessories Software/Firmware support Pre Requisites Basic Calculus Trigonometry Mechanics, specifically Newton s Laws C Programming

4 Fundamentals of inverse kinematics Project title: SCARA Robot For Mechanical Engineering students Detailed project contents 1. Introduction to the project Detailed problem definition Task: Basic problems pertaining to mechanics. Industrial applications of SCARA Forward and Inverse kinematics. What is forward kinematics? Need for inverse kinematics. Explain Jacobian in simple terms. Need of Profile generation. Avoiding jerks, in CNC jerk must be minimum. Sudden change may not be achievable by motor. Mechanical considerations. Following points will be elaborated in this sub-topic: Cantilever beam design. Placement of motor, deflection of beam, length of arm Transmission element design. Gear ratio. Belt and pulley design. Revolute joint design. Possible designs, advantages and disadvantages of each Pen Lifting mechanism. Possible designs, advantages and disadvantages of each

5 2. API guide Using Stepper Motor. Using UART Using Timer. Task: Get the motor running in direction and speed (PWM). Speed will be determined in accordance with the input from UART. 3. Speed Profile Generation Different types of speed profiles and their advantages. Simple trapezoidal, Double trapezoidal, S-Shaped. How to implement: simple trapezoidal profile. Writing actual C code on PC. This will help him maintain modularity. Task: Here the user will be required to generate speed profiles for some distances. Plot the graph and verify the working of the code. The user shall also verify the joint speeds corresponding to the trajectory generated and determine whether such joint speed profile is achievable. He will thus be able to tune MAX_ACCELERATION. 4. Forward and Inverse Kinematics Determination of forward kinematics for SCARA. Solution of inverse kinematics for SCARA to determine Inverse Jacobian to convert motion in global/cartesian space to motion in joint space. Intermediate steps may be given to aid him in the determination of the equations. Examples of other systems may be given.

6 5. Apply the Speed Profile for different Paths This milestone, unlike the previous milestone, relates to finding individual velocities of each motor. How to make the tool/pen draw a straight line between any two points. How to make the tool/pen draw a circular path. Task: Implement the same on PC and verify by drawing graphs using forward kinematics. 6. Working with actual hardware. Determination of workspace Consolidate the above written codes with the stepper driving. At this stage we have the joint velocities in rad/sec. After consolidation he will have to convert rad/sec into steps/sec using appropriate conversion factors. Conversion factors include pulley diameter ratio, radian to steps, seconds to ticks, etc Task: Write your name on a paper

1. Introduction 1 2. Mathematical Representation of Robots

1. Introduction 1 2. Mathematical Representation of Robots 1. Introduction 1 1.1 Introduction 1 1.2 Brief History 1 1.3 Types of Robots 7 1.4 Technology of Robots 9 1.5 Basic Principles in Robotics 12 1.6 Notation 15 1.7 Symbolic Computation and Numerical Analysis