One of the most common robots in the manufacturing world is the robotic arm. The robotic arm is in most cases programmable and used to perform specific tasks, most commonly for manufacturing, fabrication, and industrial applications. Article by Ahmad Alshidiq.
An industrial robotic arm is a device that operates in a similar way to a human arm, with a number of joints that either move along an axis or can rotate in certain directions. In fact, some robotic arms imitate the exact movements of human arms. They also resemble our arm, with a wrist, forearm, elbow and shoulder. The six-axis robot has six degrees of freedom, allowing it to move six different ways, unlike the human arm, which has seven degrees of freedom.
Industrial robotic arms, however, move much faster than human arms. An industrial robot arm increases the speed of the manufacturing process, the accuracy and precision. These robotic arms cut down on worker error and labour costs. Also, the quality of the product begins to improve because of the robot’s ability to, for example, accurately sand down edges, produce straighter welds or drill precise holes. This just continually improves the product over time, while also improving the integrity of the brand. But robotic arms need proper safety measures, else it can pose safety hazard to humans.
Sensors and Vision Robotics
An important advancement in the use robotic arms is the development of sensors. Robotic arms usually have sensors to perform specific tasks and to ensure the safety of human workers. Although early robots had sensors to measure the joint angles of the robot, advances in robotic sensors have had a significant impact on the work that robots can safely undertake. A summary of some of these sensors according to Design Robotics:
- 2D Vision sensors incorporate a video camera which allows the robot to detect movement over a specific location. This lets the robot adapt its movements or actions in reference to the data it obtains from the camera.
- 3D Vision Sensors are a new and emerging technology that has the potential to assist the robot in making more complex decisions. This can be achieved by using two cameras at different angles, or using a laser scanner to provide three-dimensional views for the robot.
- A Force Torque sensor helps the robotic arm to understand the amount of force it is applying and allows it to change the force accordingly.
- Collision Detection sensors provide the robot an awareness of its surroundings.
- Safety Sensors are used to ensure people working around the robot are safe. The safety sensors alert the robot if it needs to move or stop operating if it senses a person within a certain range.
There are many other sensors available which include tactile sensors or heat sensors. The benefits of these different types of sensors for robotic arms are that they provide the robot with detailed and varied information from which it can make decisions. The more information the robot has available to it, the more complex decisions it can make. Ultimately the purpose of these sensors is to help make working environments around robots safe for people.
The industrial robotic arm, which is usually made of steel or cast iron is built from the base up, ending with the wrist and whatever end effector is needed to perform the arm’s chosen task. A robotic controller rotates motors that are attached to each joint. Some of the larger arms, used to lift heavy payloads, are run by hydraulic and pneumatic means.
The arm’s job moves the end effector from place to place – picking up, putting down, taking off or welding a part or the entire work piece. These robotic arms can be programmed to do several different jobs or one specific job.
What comes after the robot’s wrist, and what’s added around the robot, varies depending on the application. But no matter the application, your robot will always need to be equipped with other components in order to work properly. These components might include end-of-arm tools (grippers, welding torches, polishing head) and sensors (such as force-torque sensors, safety sensors, vision systems).
When factories install a robotic cell, their purpose is to automate a process. That process could be one that’s currently done at a manual cell, or it could be an entirely new function. A robotic arm comes with two important elements, according to MachineDesign: the controller, which is the computer that drives its movement, and the teach pendant, which is the user interface that the operator uses to program the robot.
These metal marvels will continue to operate in manufacturing for years to come – arms lifting and moving progress along until the next lightning fast innovation is introduced. All these benefits continue to grow as robots continue to improve and enhance over time.
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