With the growing miniaturization and capabilities of robotic systems, engineers are under greater pressure to optimize all aspects of mechanical and electrical integration. A frequent problem is the ability to route power, communication and sensor cables through moving joints without introducing additional complexity and/or restricting movement. The hollow shaft planetary actuator overcomes this problem by enabling cables to run through the middle of the actuator, for cleaner layouts, greater protection and improved system efficiency. This design is gaining more and more importance in the field of robotics, industrial automation, and advanced motion control.
1.Why Cable Routing Is a Critical Part of Robotic System Design
Cable management is more than just an organizational job. Cables constantly move with rotating joints in robotic systems, thus are susceptible to bending stress, twisting, abrasion, and accidental damage. Bad routing can lead to decreased reliability, maintenance challenges and space-consuming routing.
In traditional external cable routing, extra brackets, cable chains, clamps and protective sleeves are required. These parts are useful for assembling wiring, but they can make assembly more complicated and can affect the range of motion of the robot.
These problems are addressed in modern actuator designs that incorporate the cable pathway within the actuator. Internal routing reduces cable exposure and simplifies the mechanical design for long-term reliable operation.
2.Internal Routing Creates a Cleaner and More Efficient Mechanical Layout
The biggest benefit of hollow shaft technology is that it allows us to simplify the physical structure of robotic joints. Rather than running electrical cable around the moving parts, the engineers can now run it through the central bore of the actuator.
This setup minimizes external wiring and enhances packaging efficiency. It also enables designers to create thinner joints in robots without compromising their performance.
Advantages of Internal Cable Routing
- Reduces external cable clutter around moving joints
- Protects cables from mechanical wear and accidental contact
- Improves space utilization inside compact robotic assemblies
- Simplifies assembly and maintenance procedures
- Supports cleaner mechanical integration across multiple joints
This will also allow engineers to minimize the number of external wires, which will enhance the movement of air and minimize the interference between the moving parts and allow for easier inspection and maintenance of robotic systems during their useful lives.
3.Hollow Shaft Planetary Actuator Design Supports Smarter Integration
A Hollow Shaft Planetary Actuator is characterized by its hollow center bore through which cables, communication lines or pneumatic tubes pass through the actuator and not around it. This seemingly simple design feature greatly enhances the integration options in modern robotic systems.
For instance, the AKH Series Hollow Shaft Planetary Actuator modules have an internal cable routing hollow bore of 7 mm. This allows engineers to keep wiring outside of the joint simple while keeping the joint dimensions compact.
These actuator modules contain a number of critical elements within a single housing, such as a brushless motor, precision planetary gearbox, two high-resolution 21-bit encoders and an integrated drive with Field Oriented Control (FOC) in addition to cable routing. These components can be integrated into a single module, minimizing the need for multiple components that need to be installed and connected.
The actuator also offers a variety of control modes such as SERVO and MIT control, which enable coordinated control of position, velocity and acceleration. Adaptive PID functionality also helps to make commissioning easier by minimizing manual tuning and ensuring stable motion control.
The integrated architecture helps to reduce electrical wiring, installation time, and to improve the uniformity of multi-joint robotic systems.
4.Compact High-Torque Performance Without Increasing System Complexity
Increasingly, modern automation requires actuators that are compact yet have a high output. Compact equipment can have very little space available for large transmission systems and bulky motor assemblies.
Planetary actuators solve this problem as they not only provide efficient torque transfer, but also are compact in size. Integrated actuator modules also help to simplify installation since there are fewer separate mechanical and electrical parts.
The AKH70-48 V1.0 KV41 is an example of this balance, with a rated torque of 74 Nm, a maximum torque of 222 Nm, and a weight of about 1,396 g. It is about 90mm × 81.5mm with a maximum torque density of 159 Nm/kg, offering a solid joint performance in a relatively small package.
The same applies to the AKH70-16 V1.0 KV41, which weighs about 879 g, has a peak torque of up to 85 Nm and a no-load speed of 105 RPM, ideal for use in applications where higher speed and lower weight are desired.
These integrated designs enable engineers to select a joint that provides excellent joint performance with little to no increase in system size or installation complexity.
5.Robotic Motor Integration Improves Motion Control and Reliability
Its torque output does not just determine the ability of any Robotic Motor to perform well, but also by the way it interfaces with sensors, control electronics and mechanical transmission components. This relationship is optimized with highly integrated actuator modules where all the necessary elements of motion control are integrated into one coordinated system.
Integrated Features That Enhance Motion Performance
- Brushless motor combined with precision planetary gearbox
- Dual 21-bit magnetic encoders for accurate closed-loop feedback
- Integrated FOC-enabled drive for efficient motor control
- Coordinated position, velocity, and acceleration control
- Adaptive PID tuning for simplified commissioning
Dual encoders are used to give feedback about motor position as well as output position to allow for accurate closed-loop operation and to maintain output position during power loss. This helps to increase positioning accuracy and to make the system more robust.
Stable actuator performance in demanding operating environments is further enhanced by built-in protection features, such as protection against overcurrent, overvoltage, undervoltage and overtemperature.
6.Flexible Connectivity Supports Advanced Multi-Joint Systems
Robotic systems are becoming increasingly sophisticated, and the need for communication between multiple actuators becomes more important. If the movement involves several joints, it’s important that the data is transmitted reliably and that the electrical connections are efficient.
These needs are met by modern actuator modules that incorporate communication interfaces into the design of the actuator. The AKH Series is able to handle dual CAN interfaces, enabling several actuators to be daisy-chained together for easy wiring in complex robotic assemblies.
The power and CAN communication are combined via an XT30PW (2+2) connector, and configuration and parameter tuning are possible via a dedicated UART interface from the PC. These interface options offer flexibility when integrating the system and when maintaining it.
This type of connectivity is especially beneficial in applications like robotic arms, humanoid robots, quadrupeds, exoskeletons, and industrial automation systems, where multiple joints need to work in sync.
Many manufacturers have taken up this very integrated approach, integrating motors, gearboxes, encoders, drive electronics, and communication interfaces into compact actuator modules designed specifically for advanced robotic applications, such as CubeMars.
7.Choosing Integrated Actuator Technology for Future Automation
Automation equipment continues to develop in the direction of smaller and lighter, more capable. With the growth of system complexity, minimization of unnecessary components is one of the engineering goals.
Integrated hollow shaft planetary actuators help achieve this by streamlining the cable routing, minimizing the need for wiring, optimizing packaging and enabling accurate closed-loop control in a small package size. Internal cable routing also keeps the sensitive wiring protected and provides more design flexibility in rotating joints.
They can also be customized to make parameter, interface and functional changes for various applications without changing the basic architecture of the actuator.
In the fields of robotics that are advancing all the time, whether that’s industrial automation, mobile robotics, collaborative systems or intelligent machines, actuator designs that feature mechanical efficiency and simplified integration will be increasingly important.
Conclusion
Cable routing is a crucial part of developing reliable, compact, and efficient robotic systems. Hollow shaft planetary actuator features internal cable routing to minimize external wiring and safeguard critical connections while allowing for cleaner mechanical integration through moving joints. By pairing them with integrated brushless motors, precision planetary gearboxes, dual encoder feedback, advanced control functions and flexible communication interfaces, these actuators form an effective basis for modern automation. In the context of the increasing demands of advanced robotics and industrial automation, solutions like the AKH Series illustrate the importance of integrating actuators with careful consideration of installation efficiency, motion precision, and overall system performance.