Jawaharlal Nehru Technological University Hyderabad B.Tech III Fundamentals of Robotics Previous Question Paper (January/February - 2021 - R16)

Robot anatomy based on geometrical configurations refers to the physical arrangement of links and joints that define the workspace of the manipulator. The primary classifications are:

1. Cartesian (Rectilinear) Configuration: Consists of three prismatic joints (PPP) oriented along the X, Y, and Z axes. It provides a rectangular workspace and is highly accurate for pick-and-place operations.
2. Cylindrical Configuration: Comprises one revolute joint at the base and two prismatic joints (RPP). The workspace is a cylindrical volume, making it suitable for reaching into machines or handling cylindrical objects.
3. Spherical (Polar) Configuration: Uses two revolute joints and one prismatic joint (RRP). The arm rotates about the base and shoulder, with a telescoping link, creating a spherical workspace.
4. SCARA (Selective Compliance Assembly Robot Arm): Features two parallel revolute joints providing compliance in the horizontal plane and a third prismatic joint for vertical motion (RRP). It is optimized for high-speed assembly tasks.
5. Articulated (Anthropomorphic) Configuration: Consists of three revolute joints (RRR) mimicking a human arm. It offers the most flexibility and a large, complex workspace, ideal for welding or painting.

Tactile sensors provide robots with the sense of touch, allowing them to detect contact forces and object properties.

1. Resistive Tactile Sensors: These sensors use conductive elastomers or polymers whose electrical resistance changes when compressed by an external force. As pressure is applied, the contact area increases, decreasing the resistance. They are typically used for detecting contact presence and measuring grip force. Their range is generally limited to low-to-medium pressure applications, often found in robotic grippers for handling delicate objects.
2. Capacitive Tactile Sensors: These consist of two conductive plates separated by a flexible dielectric material. When pressure is applied, the distance between the plates decreases, changing the capacitance of the sensor. These sensors are highly sensitive and capable of detecting very light touches. They are widely used in advanced robotic skins and high-precision tactile arrays to measure pressure distribution and surface texture, with a range sensitive enough to detect micro-newton variations.