When you first start designing or developing a robot, there is one question many developers run into early on: “Which robot actuator should I use?” A higher output does not automatically mean a better fit. Requirements vary depending on the robot’s structure and intended purpose, which makes it surprisingly difficult to establish clear selection criteria. With so many robotic systems emerging today, choosing the right robot actuator has become more than just picking a component — it is a core decision that shapes the overall performance of the entire robot. So what exactly does it do, and what criteria should guide your selection?
Table of Contents
What Does a Robot Actuator Do?
Key Summary An actuator converts the target values calculated by the robot into actual rotational or linear motion to move the robot’s joints and support loads. It is typically composed of a motor and a gearbox, and may also include a control unit. Requirements differ by industry and robot type.
Just as humans use muscles to walk or lift objects, robots rely on actuators to move their joints and support loads. An actuator converts the target values calculated by the robot into actual rotational or linear motion. It is typically composed of a motor and a gearbox, and may also include a control unit depending on the application.
Robot actuators are used across a wide range of industries, including manufacturing automation, logistics, production, mobility, and collaborative robotics. The performance requirements naturally differ depending on the characteristics and environment of each industry.
Requirements also differ by robot type. Industrial robots, which handle heavy-load tasks, tend to treat durability and torque output as primary considerations. Collaborative robots, operating in close proximity to people, often place importance on the ability to respond flexibly to external forces alongside output power.
What to Consider When Selecting a Robot Actuator
Key Summary A higher-output actuator is not automatically the right choice. Two fundamental factors are torque and reduction ratio, which trade off against speed. Actuator selection is a process of evaluating each robot joint individually against its own requirements, rather than applying a single criterion to the entire robot.
As this shows, a higher-output actuator is not automatically the right choice. The required performance must be closely reviewed based on the robot’s purpose and the specific role of each robot joint.
Two of the most fundamental factors to examine are torque and reduction ratio. Increasing the reduction ratio delivers more torque but reduces speed, while lowering the reduction ratio increases speed but reduces output torque.
This means the balance between force and speed needs to be configured differently for each robot joint based on its function. A joint that supports heavy loads will need a reduction ratio that secures high torque, while a joint that performs rapid repetitive movements may be better suited to a configuration that prioritizes speed.
In other words, robot actuator selection is not about applying a single criterion to the entire robot. It is a process of evaluating each robot joint individually against its own set of requirements.
Bonsystems’ Custom Actuator Lineup: BCSA V4 Series
Key Summary The BCSA V4 Series is a custom actuator lineup developed for robot development. With a range of reduction ratio options and a housing structure that separates the motor and reducer, it lets different reduction ratios be applied within the same platform without changing the external dimensions, within a slim form factor.
Given how varied the requirements are across different joints in a robot, finding a commercial actuator on the market that exactly matches each joint’s specifications can be a real challenge. With this in mind, we have focused our research on developing robot actuators optimized for robot development, designed to address the different demands of each joint effectively.
Our BCSA V4 Series offers a range of reduction ratio options, including 19:1, 29:1, 39:1, and 49:1, as listed on the official Bonsystems website, allowing you to select the specification that matches the required torque for each joint. By applying the appropriate reduction ratio at the design stage, you can improve both development efficiency and the overall quality of the final product.
The BCSA V4 Series also features a housing structure with separated motor and reducer. This design allows different reduction ratios to be applied within the same platform without changing the external dimensions, offering practical advantages in terms of development speed and lineup scalability.
We offer actuators capable of delivering a variety of reduction ratios within a slim form factor, helping to reduce the burden of design-stage evaluation and making it easier to apply the right drive configuration for your development goals. We also provide broad support across the entire development and production process, working alongside customers from the earliest stages of a project to review application environments and required specifications together.
If you need support selecting the right robot actuator for your application or reviewing applicable specifications, Bonsystems is ready to propose a drive solution tailored to your design requirements.
FAQ
Q: What should I look at first when selecting an actuator?
A: It is important to examine the factors that influence actual operating conditions together. For example, required torque, reduction ratio, and characteristics such as back-drivability may need to be carefully reviewed depending on how the robot moves and what it is designed to do. Each robot joint plays a different role, and even within the same system, the required force, speed, and response characteristics can vary. Rather than simply comparing product specifications, it is more appropriate to consider what tasks the robot will perform and under what conditions each joint will operate.
Q: What additional conditions should I keep in mind when evaluating actuators for collaborative robots?
A: It is worth examining safety-related factors alongside output performance. Characteristics such as back-drivability can become important evaluation criteria depending on the application environment. The closer a robot operates to people, the more necessary it becomes to consider not only smooth task performance but also the ability to respond to unexpected situations. Ultimately, selecting an actuator for a collaborative robot calls for a balanced evaluation based on the operating environment and usage pattern, rather than judging by force and durability alone.
Q: Can I get support reviewing drive units or robot actuators to match my intended robot structure?
A: Because the required torque, reduction ratio, mounting structure, and dimensional constraints differ from joint to joint, it is not always straightforward to apply standard specifications directly. In these cases, it helps to review the robot’s structure, purpose, and development direction together in order to define the drive unit specifications best matched to your needs. Bonsystems supports customers in reviewing actuator specifications based on the application conditions of the robot they have in mind. Feel free to reach out anytime if you need assistance with drive unit selection or specification review.
