The precision of industrial robots.

Release time:

2023-02-17

Repeatability or repeat positioning accuracy refers to the degree of difference in the robot's repeated target positions. It indicates the dispersion of the robot's position when commands are given at the same location over several consecutive attempts. This is a measure of the strength of the error, that is, the repeatability.

The precision of industrial robots

Repeatability or repeat positioning accuracy refers to the degree of difference in the robot's repeated target positions. Or under the same position command, the robot's position disperses over several consecutive repetitions. This is a measure of the strength of the error, that is, repeatability.

Common materials used in industrial robots, such as carbon structural steel and alloy structural steel, have good material strength, especially alloy structural steel, which increases by 4 to 5 times, enhancing the strength and elastic modulus E's resistance to deformation, making it the most widely used material.

Light alloys like aluminum and aluminum alloys share the common characteristic of being lightweight, with a relatively small elastic modulus E, but due to their low material density, the ratio of E/ρ can still be comparable to that of steel.

Some rare elements significantly improve the quality of aluminum alloys, such as adding 3.2% (by weight) of aluminum-lithium alloy, which increases the elastic modulus by 14%, and the E/ρ ratio increases by 16%.

Fiber-reinforced alloys, such as boron fiber-reinforced aluminum alloys and graphite fiber-reinforced magnesium alloys, have E/ρ ratios of 11.4 x 10^7 and 8.9, respectively. These fiber-reinforced metal materials have a very high E/ρ, but they are expensive.

Ceramic materials have good quality but are very brittle and difficult to process. Japan has already trial-produced ceramic samples for small high-precision robot arms.

Fiber-reinforced composites have a good E/ρ ratio and also have the advantage of significant damping. Traditional metal materials cannot achieve such high damping, so the application of composites in high-speed robots is becoming more common.

Increasing viscoelastic damping materials in robot linkages is an effective way to improve the dynamic characteristics of robots. Currently, there are many methods to increase structural damping materials, and one of the most suitable methods for robots is to use large viscoelastic damping material constraint layers.