The mid-20th century was the key period of robotic research and development, especially in an industrial environment where repetitive motions and the lifting of heavy objects made the use of machines appealing to humans. Most of the robots were used for tasks that were too dirty, remote or dangerous for humans
As per the definition is given by the International Federation of Robotics, 2013, ISO 8373 standard’s, a robot is:
An automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications.
Further description of these terms in this definition is as follows:
Reprogrammable – motions or auxiliary functions may be change without physical alterations
Multipurpose – capable of adaptation to a different application possibly with physical alterations.
Axis – an individual motion of one element of the robot structure, which could be either rotary or linear
Robotics is a multidisciplinary field that incorporates the fields of mechanics, electronics, computer science, cybernetics, artificial intelligence, physics and mathematics
Design of Industrial Robots
Industrial robots consist of six basic components: the dynamic unit, the end-of-arm machine, the digital computer controller, the actuators, the input devices and the detector.
Dynamic system the moving part of the robotic system including the robotic arm. The structures of dynamic systems are accomplished through connecting a number of rotary and/or linear motions or joints, .
That joint provides movement that can collectively place in a specific position the robot structure, or robot arm. There are different kinds of such configurations listed below:
1. Articulated configuration
Articulated arm or joint arm is the most common type of arms, closely resembles to a human arm.
These are usually six axis machines, although there are some seven axis machines available, which provide redundancy and thus improve access to uncomfortable spaces.
There are six rotational joints in the system, each placed on the previous joint. They have the ability to reach a point within the working envelope in more than one configuration or to place a device in any position.
2. SCARA configuration
This four-axis arm basically used for assembling purposes. They are small in size but has the largest carrying capacity.
The four-axis arm consists of a base rotation, a linear vertical motion accompanied in the same vertical plane by two rotating motions. The arm is very rigid in the vertical direction due to the nature of the configuration and can also ensure compliance with the horizontal plane
3. Cartesian configuration
Cartesian robot are simple three-axis robots, include only linear drives for their three major axes. Mostly used for pick and place purposes, handling, palletising, plastic moulding, assembly and machine tending.
These machines are often limited to three axes, although some special versions with additional rotating axes mounted on the last linear axis have been developed.
4. Parallel configuration
One of the new design developments is the parallel or delta robot configuration, figure below.
It involves devices with simultaneous prismatic and rotary joints in their bodies. These were designed as overhead mounted machines with the motors in the base structure driving linked arms underneath.
Due to the lesser weight of the system, it provides quick action. Therefore, the main application is picking, particularly on packing lines, and also assembly applications
5. Cylindrical configuration
Such robots combine rotary and linear axes, usually with a base rotation followed by a vertical and horizontal linear axis and additional rotating axes at the hand.
These provide a rigid structure, good cavity access, and are easy to program and visualize. We need clearance at the rear of the leg, though.
Arm end tool:
To perform some specific procedure, the robots ‘ arms can be used to attach equipment such as clamps, welding weapons, electromagnets, suction pads, hooks, or paws, etc.
A clamp is a robotic arm tool that is multifunctional. A clamp can be used to hold tight and turn things, keep and transmit components or tools, and make them to direct in a suitable position.
Robots use sensors to identify and evaluate the change in position, difference in patterns and the hinders or failure of external systems.
Actuators control each of the axes and maintain the direction of moving. Since robots need to handle weights from various components, it has a larger change in motion. Therefore, the motion of actuators is very important.
Commands are sent from the robots ‘ computer about the direction of movement and feedbacks are continuously reviewed to ensure that the moving parts follow the correct course. This process requires the sending of commands by a high-speed device and reading the movement of the system at a reasonable speed.
For robots, the computerized control system controls each component for proper operation. It can input and store various programs where it is possible to determine working sequence connections and relationships.
The device in the robots may need to control or link in a process system to other machines such as the chain, the process machines, etc.
Most robots often use a system called the trainer connected to controller. For example, to guide the welding gun in the robotic arm to each welding tip, the instructor may monitor some of a robot’s motions.
A robot’s feedback devices measure each axis ‘ position, moving speed, and acceleration. Axis must set any point as zero as the point of reference, so relatively linear motion can be implemented.
Typically the clamp uses absolute measurement values, however. It is because the location of the clamp must be maintained when the robot begins to work.
How choose a perfect Industrial robot ?
The selection of a robot for a specific application is depended on the robot’s capabilities and quality needed to meet the application’s needs as well as the requirements of the solution built for that application.
The selection of robots and how to use them should be aimed at achieving this objectives:
The robot arm is usually shown as an image and/or diagram showing the type of structure, such as articulated, SCARA, or delta.
Number of axis:
The number of axes, such as the working ranges and speeds, is indicated or can be determined from other sheet data.
This is normally stated and shown on the working envelope. On the same datasheet, there may be variants of the model with different capabilities.
The total wrist payload is usually defined. The data sheet can display design variants with different load capacities.
Repeatability both position and path
Point repeatability is normally considered.
Axes working ranges and speeds:
Typically determines the operating distance and maximum speed for each axis.
Robot mounting capabilities:
This is claimed if the robot can be placed in different directions, such as wall or upright mounting.
Protection and environmental capabilities:
This would include the default arm IP ranking as well as any choices. Other choices may also be listed, such as clean room (electronics), washdown (food) or foundry (hot, dirty applications).
The supply requirements and power usage may be stated. The robot controller’s capabilities will be important in addition to the characteristics of the robot arm, and these are often defined in a separate data sheet.
Benefits of Robots
As per ISO these are the 10 benefits of using robots:
- Reduce operating costs
- Improve product quality and consistency
- Improve quality of work for employees
- Increase production output rate.
- Increase product manufacturing flexibility.
- Reduce material waste and increase yield
- Comply with safety regulations and improve health and safety in the workplace.
- Reduce labour turnover and difficulty of recruiting workers.
- Reduce capital costs.
- Save space in high value manufacturing areas.