Slip Rings in Robotics: Enabling Rotational Joints

Introduction

Nowadays, robots have replaced humans in performing numerous tasks across various industries. Whether it's industrial robots, consumer-grade robots, or specialized robots, slip rings play a crucial role in ensuring smooth operations and precise movements. In this article, we will delve into slip rings in robotics and explore their operational principles within systems.

What Are Slip Rings?

The slip rings，also known as a rotary joint, it transmits electricity, signals, or data through contact or non-contact methods while rotating. It can also transfer other media such as liquids, gases (or vacuum), and is designed to simultaneously handle these components in some cases. It is Installed in rotating interfaces, these Slip rings enable power and signal transmission in robotic or mechanical rotation systems, thereby achieving specific functionalities of robots.

Why Robotics Needs Rotational Joints

Rotational joints provide a flawless movement without restrictions. Let's know a few cases here.

Industrial robots

Industrial robots are widely used in such processes as painting, handling, welding and so on. Taking welding robot as an example, the special design of slip ring by NBG can transmit gas, current and signal at the same time, helping welding robot to achieve high precision and high quality welding work.

Consumer-grade robots

Consumer robots, such as sweeping robots and toy robots, are commonly used to transmit current and signals using miniature slip rings or Capsule slip rings.

Sewer Robot

Sewer robots can complete the inspection and repair of underground pipe network. Usually, the slip ring of sewer robot needs to have the function of SDI high-definition video signal transmission. NBG usually designs the slip ring with IP68 protection grade, using gold-gold connection, maintenance-free, long life and high reliability.

Deep-sea robots

NBG has designed multiple slip rings specifically for deep-sea robots, typically featuring IP68-rated sealing. These components integrate current transmission and FORJ (Fiber-Optic Remote Junction) technology. Notably, the NBG slip ring employs capacitive coupling wireless transmission technology to achieve over 1Gbps data transfer rates, while also utilizing magnetic coupling wireless current transmission. This innovative design enables fully wireless operation, ensuring maintenance-free performance, high reliability, and extended service life.

Challenges in Maintaining Continuous Signals During Rotation

What happens if there is no slip ring installed? Here it is:

● Twist and break in the joints and cables over time due to repeated movement.

● Signal loss and electrical downtime due to disconnections or damage can hurt the smooth operation.

Slip rings ensure a smooth experience and provide a free rotation without bending or twisting of components. Moreover, they keep the components engaged.

Benefits of Slip Rings in Robotic Applications

Slip rings are ideal for robotic applications. Why? Because of the following benefits.

Compact and Lightweight Form Factor

They have a compact structure and lightweight material. Plus, their installation increases the speed and motion of the robotic applications while keeping the signal integrity at the top.

Reliable Power and Signal Transmission

The goal of the cap slip ring is to maintain the flow of power and signal between the rotating and stationary components of the machines and robots. During rotational movements, slip rings ensure a power and signal delivery across analog, digital, Ethernet, or power lines.

High-Speed Rotation Support

Many robotic applications require constant and high-speed rotational movements. This is the feature of slip rings as well. They have a high RPM and work with the speedy systems without losing much energy or causing excessive heat production.

Low Electrical Noise for Precision Control

In sensitive robotic operations, there is a need for signal integrity. A slight disruption can move the rhythm. Therefore, you have to consider low electrical noise and constant signal transmission. Capsule slip rings are designed to produce low electrical noise and provide integral signals continuously.

Long Operational Life with Minimal Maintenance

The robust structure and effective construction make them stay longer in this game. Moreover, the housing further protects the slip rings from dust accumulation. Thanks to gold-on-gold contacts that keep the friction and wear as low as possible, leading to extended longevity.

Key Features of Slip Rings for Robotics

Slip rings are compatible with robotic applications and offer crucial functionality. Here are a few features that make it compatible.

Miniaturized Design

Modern robotic designs, especially in drones, medical robots, or precision robotic arms, demand minimal space usage. It is because of free movement. Thanks to the miniature design of the cap slip rings, which provides a lightweight installation and compact assembly.

Low Torque and Smooth Rotation

Low torque of the slip rings causes less friction during rotation. It helps reduce the chances of wear and provides a seamless rotation without significantly impacting the components.

Hybrid Channel Capability

Cap slip rings have a built-in capability to ship signals from various channels. Whether it is analog, digital, Ethernet, CANbus, USB, or HDMI signals, Capsule  slip rings ensure a stable signal transmission.

Customizable Circuit Options

Manufacturers can better tailor the slip rings to match the circuits, voltage/current ratings, and signal compatibility. Customization ensures a proper strategy to achieve high performance and better efficiency.

Durability in High-Cycle Environments

Industrial and collaborative equipment and robots require 24/7 availability and functionality. Slip rings are designed to meet all the environmental resistances and create a highly durable and top-performance system.

Design and Integration Considerations

Design and integration of the slip rings matter in the system. Here are a few ways.

Choosing the Right Channel Count

Channel counts mean the number of circuits for signal or power transmission. Depending on your needs, you can go for the correct channel count. As a safety factor, you can increase the number of channels for future upgrades.

Mounting and Space Constraints

Mounting on the rotary interface is necessary. You should consider:

● Axial vs. radial mounting options.

● Allow for wiring clearance and strain relief.

● Keep thermal expansion in mind if operating in variable temperatures.

Signal Type Compatibility

Not all slip rings handle high-speed data transmission. For various signals, you should consider:

● For Ethernet or USB, low-noise shielding and impedance matching.

● For analog signals, noise suppression.

Lifecycle Expectations and Duty Cycles

Some slip rings have to undergo continuous use while others operate intermittently. Based on usage, you should consider:

● Rated RPM (rotations per minute)

● Expected lifetime in number of revolutions

● Operating temperature and environmental sealing

Conclusion

Slip rings are compact and essential components of robots that allow continuous movement but with stable electrical connections. They reduce the chances of maintenance and improve the overall efficiency of the robots. With sensors and other tools, they also update the system in real time to avoid any errors.