Industrial robot drive systems are classified into three main categories based on their power source: hydraulic, pneumatic, and electric. Depending on the needs, these three basic types can also be combined to form a composite drive system. Each of these three basic drive systems has its own characteristics.
I. Hydraulic Drive System
Hydraulic technology is a relatively mature technology. It features high power, a large force (or torque) to inertia ratio, fast response, and ease of direct drive implementation. It is suitable for robots with high load-bearing capacity, high inertia, and those operating in weld-proof environments. However, hydraulic systems require energy conversion (electric energy to hydraulic energy), and speed control often uses throttling, resulting in lower efficiency than electric drive systems. Hydraulic systems also cause environmental pollution due to fluid sludge discharge and generate higher operating noise. Because of these weaknesses, in recent years, hydraulic systems have often replaced hydraulic systems in robots with loads below 100 kHz.
II. Pneumatic Drive System
It features high speed, simple system structure, convenient maintenance, and low price. It is suitable for use in robots with medium to small loads. However, due to the difficulty in implementing servo control, it is mostly used in program-controlled robots, such as loading/unloading and stamping robots.
III. Electric Drive System
Due to the widespread use of low-inertia, high-torque AC and DC servo motors and their matching servo drives (AC inverters, DC pulse width modulators), this type of drive system is widely used in robots. These systems require no energy conversion, are easy to use, and offer flexible control. Most motors require a precision transmission mechanism. DC brushed motors cannot be used directly in explosion-proof environments, and their cost is higher than the other two drive systems. However, because of their significant advantages, this type of drive system is widely used in robots.
