Unit 1: Fundamentals of Robot

1. (i) Explain the speed of motion in industrial robots. (ii) Explain the load-carrying capacity of a robot.

Answer:

(i) Speed of Motion in Industrial Robots:

The speed of motion in industrial robots refers to the rate at which the robot can move its end effector (the tool or gripper at the end of the robot arm) from one position to another. This speed is typically measured in units such as meters per second (m/s) or degrees per second (°/s). The speed of motion is a critical parameter in industrial applications, as it directly affects the efficiency and productivity of the robot. Factors that influence the speed of motion include the robot’s design, the type of actuators used, the control system, and the payload being carried.

(ii) Load-Carrying Capacity of a Robot:

The load-carrying capacity of a robot refers to the maximum weight that the robot can handle while maintaining its performance and accuracy. This capacity is determined by the robot’s mechanical design, the strength of its actuators, and the control system’s ability to manage the additional weight. Exceeding the load-carrying capacity can lead to reduced accuracy, increased wear and tear, and potential damage to the robot. It is essential to consider the load-carrying capacity when selecting a robot for a specific application to ensure safe and efficient operation.

2. (i) With a neat sketch explain the three degrees of freedom associated with the robot wrist. (ii) Discuss the four types of robot controls.

Answer:

(i) Three Degrees of Freedom Associated with the Robot Wrist:

The robot wrist typically has three degrees of freedom, which allow it to orient the end effector in three-dimensional space. These degrees of freedom are:

Roll: Rotation around the longitudinal axis of the wrist.
Pitch: Rotation around the lateral axis of the wrist.
Yaw: Rotation around the vertical axis of the wrist.

A sketch of the robot wrist would show these three axes of rotation, illustrating how the wrist can move in three different directions to achieve the desired orientation of the end effector.

(ii) Four Types of Robot Controls:

Point-to-Point Control: In this type of control, the robot moves to predefined positions without concern for the path taken. It is suitable for applications where the exact path is not critical, such as pick-and-place operations.
Continuous Path Control: This control allows the robot to follow a specific path with high precision. It is used in applications like welding or painting, where the robot must follow a complex path.
Adaptive Control: Adaptive control systems can adjust the robot’s behavior based on feedback from sensors. This allows the robot to respond to changes in the environment or task, improving accuracy and efficiency.
Intelligent Control: Intelligent control systems use advanced algorithms, such as artificial intelligence or machine learning, to make decisions and adapt to new situations. These systems can handle complex tasks and improve performance over time through learning.

3. (i) Classify the industrial robots and briefly describe it. (ii) Describe the major elements of an industrial robot.

Answer:

(i) Classification of Industrial Robots:

Industrial robots can be classified based on various criteria, including their structure, application, and control system. Common classifications include:

Articulated Robots: These robots have rotary joints and can move in multiple directions. They are highly flexible and are used in applications requiring complex movements.
SCARA Robots: Selective Compliance Assembly Robot Arm (SCARA) robots are designed for high-speed, high-precision assembly tasks. They have a rigid vertical axis and a flexible horizontal axis.
Cartesian Robots: These robots move along three linear axes (X, Y, Z) and are used in applications requiring precise, linear movements.
Delta Robots: Delta robots have a unique structure with three arms connected to a common base. They are used in high-speed pick-and-place applications.

(ii) Major Elements of an Industrial Robot:

Manipulator: The main body of the robot, consisting of links and joints that allow movement.
End Effector: The tool or gripper attached to the end of the robot arm, used to interact with the environment.
Actuators: Devices that convert energy into motion, such as electric motors, hydraulic cylinders, or pneumatic actuators.
Sensors: Devices that provide feedback to the control system, allowing the robot to perceive its environment and adjust its actions accordingly.
Control System: The brain of the robot, responsible for processing sensor data and sending commands to the actuators to achieve the desired movement.
Power Supply: Provides the necessary energy to operate the robot’s actuators and control system.

4. (i) Describe in detail the anatomy of an industrial robot. (ii) Describe the industrial application of robots.

Answer:

(i) Anatomy of an Industrial Robot:

The anatomy of an industrial robot includes several key components:

Base: The foundation of the robot, providing stability and support.
Manipulator: The main body of the robot, consisting of links and joints that allow movement. The manipulator can have multiple degrees of freedom, enabling complex movements.
End Effector: The tool or gripper attached to the end of the robot arm, used to interact with the environment. The end effector can be customized for specific tasks, such as welding, painting, or assembly.
Actuators: Devices that convert energy into motion, such as electric motors, hydraulic cylinders, or pneumatic actuators. Actuators are responsible for moving the robot’s links and joints.
Sensors: Devices that provide feedback to the control system, allowing the robot to perceive its environment and adjust its actions accordingly. Common sensors include encoders, force sensors, and vision systems.
Control System: The brain of the robot, responsible for processing sensor data and sending commands to the actuators to achieve the desired movement. The control system can be programmed to perform specific tasks and can adapt to changes in the environment.
Power Supply: Provides the necessary energy to operate the robot’s actuators and control system. The power supply can be electric, hydraulic, or pneumatic, depending on the robot’s design.

(ii) Industrial Applications of Robots:

Robots are used in a wide range of industrial applications, including:

Manufacturing: Robots are used in manufacturing for tasks such as assembly, welding, painting, and material handling. They can perform repetitive tasks with high precision and speed, improving efficiency and reducing costs.
Automotive Industry: Robots are used in the automotive industry for tasks such as welding, painting, and assembly. They can handle heavy components and perform complex movements with high accuracy.
Electronics Industry: Robots are used in the electronics industry for tasks such as assembly, testing, and packaging. They can handle small, delicate components and perform precise movements.
Food and Beverage Industry: Robots are used in the food and beverage industry for tasks such as packaging, sorting, and palletizing. They can handle food products safely and efficiently.
Pharmaceutical Industry: Robots are used in the pharmaceutical industry for tasks such as packaging, labeling, and quality control. They can handle sensitive products and perform precise movements.
Logistics and Warehousing: Robots are used in logistics and warehousing for tasks such as picking, packing, and sorting. They can handle a wide range of products and perform complex movements in dynamic environments.

5. Describe the specifications of an industrial robot and with its configuration.

Answer:

Specifications of an Industrial Robot:

The specifications of an industrial robot include various parameters that define its capabilities and performance. Common specifications include:

Payload Capacity: The maximum weight that the robot can handle while maintaining its performance and accuracy.
Reach: The maximum distance that the robot can extend its end effector from the base.
Speed: The rate at which the robot can move its end effector from one position to another, typically measured in meters per second (m/s) or degrees per second (°/s).
Accuracy: The ability of the robot to position its end effector at a specific location with high precision.
Repeatability: The ability of the robot to return to the same position repeatedly with high precision.
Degrees of Freedom: The number of independent movements that the robot can perform, typically defined by the number of joints in the manipulator.
Control System: The type of control system used, such as point-to-point, continuous path, adaptive, or intelligent control.
Power Supply: The type of power supply used, such as electric, hydraulic, or pneumatic.

Configuration of an Industrial Robot:

The configuration of an industrial robot refers to the arrangement of its links and joints, which determines its range of motion and capabilities. Common configurations include:

Articulated: Robots with rotary joints that allow movement in multiple directions. They are highly flexible and are used in applications requiring complex movements.
SCARA: Selective Compliance Assembly Robot Arm (SCARA) robots are designed for high-speed, high-precision assembly tasks. They have a rigid vertical axis and a flexible horizontal axis.
Cartesian: Robots that move along three linear axes (X, Y, Z) and are used in applications requiring precise, linear movements.
Delta: Robots with a unique structure with three arms connected to a common base. They are used in high-speed pick-and-place applications.

The configuration of a robot is chosen based on the specific requirements of the application, such as the range of motion needed, the payload capacity, and the speed and accuracy required.

6. (i) Sketch a robot wrist and explain its joint movements. (ii) Briefly explain the need for robots in industries.

Answer:

(i) Robot Wrist and Joint Movements:

A robot wrist typically has three degrees of freedom, which allow it to orient the end effector in three-dimensional space. These degrees of freedom are:

Roll: Rotation around the longitudinal axis of the wrist.
Pitch: Rotation around the lateral axis of the wrist.
Yaw: Rotation around the vertical axis of the wrist.

A sketch of the robot wrist would show these three axes of rotation, illustrating how the wrist can move in three different directions to achieve the desired orientation of the end effector.

(ii) Need for Robots in Industries:

Robots are essential in industries for several reasons:

Efficiency: Robots can perform repetitive tasks with high precision and speed, improving efficiency and reducing costs.
Safety: Robots can handle dangerous or hazardous tasks, reducing the risk of injury to human workers.
Consistency: Robots can perform tasks with high consistency, ensuring that products meet quality standards.
Flexibility: Robots can be reprogrammed to perform different tasks, making them versatile and adaptable to changing production needs.
Cost-Effectiveness: While the initial investment in robots can be high, they can reduce long-term costs by increasing productivity and reducing labor costs.
Scalability: Robots can be easily scaled up or down to meet production demands, making them suitable for both small and large-scale operations.

7. Classify the robots according to the coordinates of motion. With a sketch and example, explain the features of each type.

Answer:

Robots can be classified based on the coordinates of motion, which define how the robot moves in space. Common classifications include:

Cartesian Robots:
- Description: Cartesian robots move along three linear axes (X, Y, Z) and are used in applications requiring precise, linear movements.
- Features: High precision, simple control, and easy programming. They are suitable for tasks such as pick-and-place, assembly, and material handling.
- Example: A Cartesian robot used in a 3D printer to move the print head along the X, Y, and Z axes to create a three-dimensional object.
Cylindrical Robots:
- Description: Cylindrical robots have a rotary joint for rotation and a linear joint for vertical movement. They move in a cylindrical coordinate system.
- Features: Good for tasks requiring rotation and vertical movement, such as assembly and material handling.
- Example: A cylindrical robot used in a manufacturing line to pick up parts from a conveyor belt and place them in a specific location.
Spherical Robots:
- Description: Spherical robots have a rotary joint for rotation, a linear joint for radial movement, and a rotary joint for elevation. They move in a spherical coordinate system.
- Features: Suitable for tasks requiring rotation, radial movement, and elevation, such as welding and painting.
- Example: A spherical robot used in a welding application to move the welding torch around a complex part.
Articulated Robots:
- Description: Articulated robots have multiple rotary joints and can move in multiple directions. They are highly flexible and are used in applications requiring complex movements.
- Features: High flexibility, wide range of motion, and ability to perform complex tasks. They are suitable for tasks such as assembly, welding, and material handling.
- Example: An articulated robot used in an automotive assembly line to perform complex welding operations on a car body.

A sketch of each type of robot would illustrate the different axes of movement and the range of motion for each type.

8. Explain the various parts of a robot with a neat sketch.

Answer:

The various parts of a robot include:

Base: The foundation of the robot, providing stability and support.
Manipulator: The main body of the robot, consisting of links and joints that allow movement. The manipulator can have multiple degrees of freedom, enabling complex movements.
End Effector: The tool or gripper attached to the end of the robot arm, used to interact with the environment. The end effector can be customized for specific tasks, such as welding, painting, or assembly.
Actuators: Devices that convert energy into motion, such as electric motors, hydraulic cylinders, or pneumatic actuators. Actuators are responsible for moving the robot’s links and joints.
Sensors: Devices that provide feedback to the control system, allowing the robot to perceive its environment and adjust its actions accordingly. Common sensors include encoders, force sensors, and vision systems.
Control System: The brain of the robot, responsible for processing sensor data and sending commands to the actuators to achieve the desired movement. The control system can be programmed to perform specific tasks and can adapt to changes in the environment.
Power Supply: Provides the necessary energy to operate the robot’s actuators and control system. The power supply can be electric, hydraulic, or pneumatic, depending on the robot’s design.

A neat sketch of a robot would illustrate these parts, showing how they are connected and how they work together to perform tasks.

9. (i) Explain the different types of robots. (ii) What are the specifications of robots?

Answer:

(i) Different Types of Robots:

Robots can be classified into various types based on their structure, application, and control system. Common types include:

Articulated Robots: These robots have rotary joints and can move in multiple directions. They are highly flexible and are used in applications requiring complex movements.
SCARA Robots: Selective Compliance Assembly Robot Arm (SCARA) robots are designed for high-speed, high-precision assembly tasks. They have a rigid vertical axis and a flexible horizontal axis.
Cartesian Robots: These robots move along three linear axes (X, Y, Z) and are used in applications requiring precise, linear movements.
Delta Robots: Delta robots have a unique structure with three arms connected to a common base. They are used in high-speed pick-and-place applications.
Cylindrical Robots: These robots have a rotary joint for rotation and a linear joint for vertical movement. They move in a cylindrical coordinate system.
Spherical Robots: These robots have a rotary joint for rotation, a linear joint for radial movement, and a rotary joint for elevation. They move in a spherical coordinate system.

(ii) Specifications of Robots:

The specifications of a robot include various parameters that define its capabilities and performance. Common specifications include:

Payload Capacity: The maximum weight that the robot can handle while maintaining its performance and accuracy.
Reach: The maximum distance that the robot can extend its end effector from the base.
Speed: The rate at which the robot can move its end effector from one position to another, typically measured in meters per second (m/s) or degrees per second (°/s).
Accuracy: The ability of the robot to position its end effector at a specific location with high precision.
Repeatability: The ability of the robot to return to the same position repeatedly with high precision.
Degrees of Freedom: The number of independent movements that the robot can perform, typically defined by the number of joints in the manipulator.
Control System: The type of control system used, such as point-to-point, continuous path, adaptive, or intelligent control.
Power Supply: The type of power supply used, such as electric, hydraulic, or pneumatic.

10. (a) Sketch and explain the following configuration of robot. (i) TRR (ii) TRL:R (iii) RR:R

Answer:

(a) Robot Configurations:

(i) TRR (Translational-Rotational-Rotational):

Description: This configuration consists of a translational joint followed by two rotational joints. The translational joint allows movement along a linear axis, while the rotational joints allow rotation around two different axes.
Features: Suitable for tasks requiring linear movement and rotation, such as pick-and-place operations.
Example: A TRR robot used in a manufacturing line to pick up parts from a conveyor belt and place them in a specific location.

(ii) TRL:R (Translational-Rotational-Linear-Rotational):

Description: This configuration consists of a translational joint, a rotational joint, a linear joint, and a rotational joint. The translational and linear joints allow movement along linear axes, while the rotational joints allow rotation around different axes.
Features: Suitable for tasks requiring a combination of linear and rotational movements, such as assembly and material handling.
Example: A TRL:R robot used in an assembly line to pick up parts, rotate them, and place them in a specific location.

(iii) RR:R (Rotational-Rotational-Rotational):

Description: This configuration consists of three rotational joints. Each joint allows rotation around a different axis, providing a wide range of motion.
Features: Highly flexible and suitable for tasks requiring complex movements, such as welding and painting.
Example: An RR:R robot used in a welding application to move the welding torch around a complex part.

A sketch of each configuration would illustrate the different joints and the range of motion for each type.

(b) Briefly explain the following terms:

(i) Payload: The maximum weight that a robot can handle while maintaining its performance and accuracy. It is a critical parameter in selecting a robot for a specific application.

(ii) Compliance: The ability of a robot to adapt to external forces or changes in the environment. Compliance is important in applications where the robot interacts with objects or surfaces that may move or deform.

(iii) Precision: The ability of a robot to position its end effector at a specific location with high accuracy. Precision is crucial in applications requiring exact positioning, such as assembly and machining.

(iv) Accuracy: The ability of a robot to achieve the desired position or movement with high precision. Accuracy is essential in applications where the robot must perform tasks with high consistency and reliability.

Syllabus

Introduction to Robotics:
- Brief History, Definition, Robot Anatomy, Three laws, Classification of robots,
- Robot terminologies: work volume, Degree of Freedom, resolution, accuracy, repeatability, dexterity, compliance, payload capacity, speed of response etc., Wrist assembly, Joint notations, Selection criteria of any robot, Industrial applications of robot, Futuristic robotics.
Robot Drive Systems, End Effectors, and Automation:
- Types of drives – Hydraulic, Pneumatic and Electric, Comparison of all such drives,
- DC servo motors, Stepper motors, AC servo motor – salient features and applications, pulse count calculations, End effectors - Types of Grippers – Mechanical, Magnetic, vacuum, pneumatic and hydraulic, selection and design considerations.
Robot Sensors:
- Need for sensors, types of sensors used in Robotics, classification and applications of sensors, Characteristics of sensing devices, Selections of sensors.
Machine Vision:
- Robot Vision setup (RVS), block diagram, components, working of RVS, Human vision Vs Robot Vision, Gradient calculations, Applications of RVS.