Robot drive systems can be thought of as the muscular system of a robot. They’re the part of the robot responsible for how it performs tasks, such as lifting or twisting robotic arms. The muscular system in our body keeps us upright and strong, and that’s exactly how the drive system operates as well.
Following this definition, you then understand that robot drive systems are an important part of robotic systems. But how do they actually work? And what are the different kinds of drive systems that appear in robots?
For a more in-depth understanding of drive systems, continue along with this article. We’ll discuss the three main systems you should be aware of and we’ll dive into a more extensive definition of a drive system.
Drive System Fundamentals
In order to understand a drive system, you first need to familiarize yourself with actuators. Put plain and simple, actuators are mechanisms that are told to do specific tasks by a control system. They typically come in two different forms, linear and rotary. A linear actuator moves an object in a straight line. They typically have a cylinder holding cell with a piston inside that moves on a linear plane. A rotary actuator moves an object in circular motion. Just like a linear actuator, they’re controlled by a power source. However, to move an object, they use gears and coils.
It’s important to understand this because a drive system is what’s controlling these actuators. The actuators allow robots to fulfill their designated tasks, such as lifting products off of conveyor belts or spinning containers to aid in mixing certain materials. Not all drive systems are created equally, so depending on which actuator you need and the task at hand, you will be able to narrow down which drive system you need.
Drive systems are first chosen with specific attributes in mind. Acceleration, obstacle handling, climbing and ease of control are just a few examples of the attributes technicians will think about. Once this is decided, actuators are built into a robot, which can then in turn control anything from gears, belts or motors. The four basic drive systems include electric, hydraulic, mechanical, and pneumatic. Each drive system requires different parts in order to function properly, so not every system will look the same.
The Different Types of Drive Systems
Electric Drive System
This type of drive system focuses on power and speed. It’s great for moving both rotational or linear joints, and for robots that require an incredible amount of precision. They’re best for small robots, and as such, occupy less floor space on the factory floor.
As the name suggests, these drive systems function by way of electricity. They’re most commonly found in DC motors and servo motors, which allow for accurate control and angular positioning of a robot. Picking and drilling robots, for example, work best with these types of drive systems when there is little room for errors or inconsistencies. They can typically be found in a few domestic applications, like fans and pumps. But when it comes to robotics, they’re found across industries, from paper mills to aerospace technology.
Electric drive systems are excellent for precision, however, they do have some disadvantages. Their initial cost is quite high and they have a poor dynamic response.
Hydraulic Drive System
Hydraulic drive systems are specifically designed for larger robots. They deliver high power and speed, greater than an electric drive system. This system can be used for both rotational and linear joints. In this system, an electric motor drives a pump which moves fluid from a reservoir. This causes oil to pass through the control valves and enter the actuators.
While these systems deal with heavy machinery, they are generally able to operate smoothly, making seamless transitions and effortless movements. A large robotic arm driven by a hydraulic system, for example, would be great for palletization—lifting and placing large products on a pallet for a shipment.
Pneumatic Drive System
Pneumatic drive systems use compressed air, or pressurized gasses, to facilitate the movement of a robot. Air is compressed and then stored in a reservoir, and from there, the air is distributed through units to the actuators. These systems are simple to construct and they are less expensive than hydraulic systems. The compressed air can also help absorb shock.
Pneumatic drive systems work well for robots that require fluid movements and are also low maintenance. They’re found in the manufacturing industry for applications that require clamping or drilling. They’re also found in food processing plants and paper mills since the ease of motion is great for packing or filling containers. A simple example of a pneumatic system would be a nail gun. The compressed air is pushed through a system and forces out at high-speed.
However, there are some disadvantages to pneumatic drive systems. They’re typically restricted to low power applications and don’t offer much in terms of speed control.
Controlling the Motions
Drive systems play an important role when it comes to robots, and depending on the type of robot you’re looking to build or maintain, you will need to decide which drive system will work best. The three main types of drive systems all offer their advantages and disadvantages, and while all can work with the two main types of actuators, the performance outcome will be different.
Without a proper drive system, a robot wouldn’t be able to function properly. They are needed for an actuator to work so that a robot can fulfill its most basic function. If this topic interests you and you want to learn more about drive systems, or robots in general, a Robotics Technician course could be in your future. Having a good understanding of these systems and how they should be applied is an important part of succeeding as a robotics technician.
For more information, check out George Brown College Robotics Technician Program.