Robotic Manipulators / Robotic Arms

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This is a typical structure of a manipulator. A manipulator consists of Joints, Links, an End effector, and a base.
- Joints: These are the movable components of a robotic arm. Joints allow the movement of links. Actuators like motors allow the movement of joints.
- Links: These are rigid structures used to connect joints. Movement of links is possible with joints only.
- End-Effector: In serial robotic manipulators, the end effector means the last link of the robot. An end effector is a device at the end of a robotic arm, designed to interact with the environment. For example, the mechanism gives the gripping capability to a robotic arm.
- Base: It is a plane to which a robotic arm is connected.
A robotic arm is very similar to a human arm.
- Your elbow and wrist are similar to joints.
- Your forearm is like a link that connects two joints i.e your elbow and wrist.
- Your palm and fingers are the end-effectors.
- Your torso is the base for your arm.

Reading Assignment

It is a branch of mathematics that deals with the motion of a body or system of bodies.
It describes the motion of points, bodies, or systems of bodies without looking into forces that cause them to move.
Before diving deep let's look at why we need kinematics in the first place?

Suppose you have a robotic arm and you want to pick a box using this arm.
You know the position of the box in Cartesian space i.e you know the x, y, and z of the box in space.
Now in order to pick this box you need the end-effector of your robotic arm to go near the box and then pick it.
To make this possible you need to actuate the joints of your robotic arm in such a way that the end-effector is able to reach the box.
Now, how much do you need to actuate each joint for this? This is an Inverse Kinematics problem.
Given the position of the end-effector in Cartesian space you can calculate the angle of rotation for each joint using Inverse Kinematics.
If you have joint angles and you need to calculate the position of your end-effector in Cartesian space you can calculate that using Forward Kinematics.