Robots designed specifically for industrial applications can be characterized according to their operational modes, control systems, mounted tools or interactive mechanisms, and arm geometry. These machines are used for a wide range of manufacturing purposes and play a major role in industrial system automation. Generally, industrial robots are programmed with either limited or unlimited sequence control, which determines the motion paths taken by the robotic mechanism (such as a tool or a gripper) that interacts with external objects. Robotic controls can also be servo-based, relying on a closed-loop to provide feedback and enable unlimited sequence control, or non-servoed, with an open loop control that doesn’t offer feedback and relies on limited sequence motions.
An industrial robotic system has the potential to handle a wider range of duties than standard automatic machinery, even if the machinery can be equipped with multiple tooling configurations. But although they can be used as multifunctional devices, most industrial robots are designed to specialize on a specific task, such as assembling, loading, painting, or welding. Many robots can be used to perform in applications similar to their field of specialization, but operational effectiveness within a given project usually depends on factors such as the unit’s size, dimensions, weight, range, speed, repeatability of motion, load capacity, and operating cost.
Powering a Robotic System
Electric motors, hydraulic drives, and pneumatic actuators are the most common mechanisms used to power industrial robots. Electric motors feature highly efficient power sourcing and have relatively simple design characteristics, making them one of the more popular options in terms of cost-to-performance ratings. Hydraulic drives tend to be more powerful, enabling robots to have a load capacity in excess of 500 pounds, and can work effectively with volatile gases or hazardous substances that present the risk of explosion or fire for electric motors. However, hydraulic drives are more prone to maintenance issues and carry the risk of oil leakage, which can create a fire hazard in enclosed spaces. Hydraulic robot systems are also less suited for indoor work in controlled environments where they are in close proximity to personnel. Pneumatic actuators are commonly used for powering the mechanisms that interact with external objects, such as the grippers mounted on the end of electric-drive robot arms. A pair of pneumatic actuators working in unison to power a single gripper can enable it to move along multiple axes.
Axis of Motion
Range of motion is an important determinant of a robotic system’s capabilities and is usually measured by “degrees of freedom” (DOF), which refers to the number of axes a robot arm is able to traverse. A standard limited sequence robot can usually move along two or three axes, while its manipulator arm can perform a shoulder swivel, an arm sweep, or an elbow extension. By contrast, an unlimited sequence machine can execute more sophisticated motions along a larger number of axes, including pitch, yaw, and roll. A typical heavy-duty robot with complex motion capabilities, such as the one described by RobotWorx, may have as many as six main axes, with each axial motion powered by an electric motor.
Control Consoles
A robotic system console typically incorporates a digital computer featuring the operating system and application software needed for running automated tasks. A system operator can program or control robotic movements through a push-button array on the console, enabling some degree of manual control over programmed sequences. During system setup, careful adjustments are made to the programming to ensure the robot does not collide with any surrounding objects while operating.
Industrial robots can also be equipped with handheld control boxes that connect to the computerized control console through cables. These boxes often feature their own push-button arrays as well as graphical display interfaces to improve ease-of-use. In addition, a qualified operator can sometimes use a handheld control box to train a robotic unit by leading it manually through an assigned task. As the robot completes each movement along an axis, it stores the motion sequence in its memory and repeats the routine upon command.
Mounting Options
Although larger robotic systems tend to be floor-standing, some variants are designed to be mounted vertically, upside down, or at an angle to improve accessibility within a workspace. These mounting methods provide advantages for certain applications. For example, a vertically-mounted unit can be attached to a structural frame with a rail, allowing it to move a predetermined distance when performing a long weld or painting a large object. Some robots can also be placed in a fixed position on a wall or mounted to enable angular movement.
