Simulation of forward kinematics of 2R Robotic Arm using MATLAB.

AIM: Write a program in MATLAB to simulate the forward kinematics of the 2R Robotic Arm.

INTRODUCTION: A robotic arm is a mechatronic device which is usually programmable with similar function to a human arm.

The elements of the robotic arm are as follows:

• Manipulator: The links that move the robotic arm.
• Actuators: It drives the manipulators at the joints. It is similar to the muscles which are present in human beings.
• Processor: It acts like a brain of the robotic arm that calculates motion.
• Controller: It sends inputs to control the actuator motions.
• End effector: It is that part of the robot that interacts with the environment or external stimulus.
• Sensors: It has the function to sense internal and external changes to the physical environment.

KINEMATICS OF ROBOTIC ARM: The kinematics of robotic arm tells about the relationship between position, velocity and acceleration of links and joints. The position, velocity and acceleration can be angular or linear also. There are two types of robot kinematics i.e., forward kinematics and inverse kinematics.

FORWARD KINEMATICS: It is the type of robot kinematics in which it is meant for determining the orientation and position of end effector given the joint angles and link lengths of the robotic arm.

INVERSE KINEMATICS: It is the type of robot kinematics in which it involves the computation of joint angles based on the required position and orientation of the end effector.

ABSTRACT: The 2R Robotic arm consists of two links and two rotational joints.

The base of link1 is fixed at (0,0) and the end of link1 is at (x1,y1). The length of link1 is 1m. The link1 is making an angle of theta1 with respect to the horizontal line. So, the coordinates of x1 and y1 in terms of l1 and theta1 will be x1=l1*cos(theta1) and y1=l1*sin(theta1). The base of link2 is joined at the end of link1 through rotational joint and the coordinate of base of link2 will be (x1,y1). The length of link2 is 0.5m. The link2 is making an angle of theta2 as shown in figure. The coordinate of end of link2 is (x2,y2) and we can express this coordinate as x2=x1+l2*cos(theta2) and y2=y1+l2*sin(theta2). The end effector is connected at the end point of link2 for welding or machining purposes.

Hence, x1=l1*cos(theta1) x2=x1+l2*cos(theta2)

y1=l1*sin(theta1) y2=y1+l2*sin(theta2)