Table of Contents
Service robots are designed to support people in their daily lives and work across a wide range of environments. Their applications are expanding from familiar tasks such as transporting goods and guiding customers to rehabilitation assistance, object handling, and everyday support in the home.
As the range of applications expands, the roles performed by service robots are also becoming more diverse. In addition to moving along predefined routes, service robots are increasingly expected to grasp and move objects, assist human movement, and perform tasks using articulated arms, leg mechanisms, lifting systems, and other driven structures.
To perform these tasks in human-centered environments, service robots need to maintain a compact form factor while providing sufficient torque at each joint.
The expansion of the service robot market is therefore driving changes not only in the design of complete robotic systems but also in the structure and development of key drive components such as reducers and actuators.
The Expanding Application Range of Service Robots
Key Summary Service robots are expanding beyond guidance and transportation to provide more direct assistance with movement, object handling, and everyday tasks.
Service robots are primarily used in environments where people live, work, and interact rather than on fixed industrial production lines.
Common examples include guidance robots that provide information to customers in stores and transport robots that carry goods in hotels, restaurants, hospitals, and other facilities.
More recently, service robots that combine mobile platforms with robotic arms or lifting mechanisms have also been developed to handle objects directly.
In medical and rehabilitation applications, wearable and assistive robots can support the movement of a user’s arms or legs. In homes and other everyday environments, robots designed to move objects and assist with routine tasks are also being developed.
As the role of service robots continues to expand, simple point-to-point mobility is no longer sufficient for the growing range of tasks they are expected to perform.
Robots may need to adjust their posture according to the surrounding environment, move multiple joints based on the location and shape of objects, and operate reliably in close proximity to people.
These changes are increasing the importance of compact, responsive, and application-specific drive systems.
Service Robots Operating Around People
Key Summary Because service robots operate in spaces used by people, their overall size, movement, noise levels, and drive-unit configuration must be considered together.
In factories, large equipment can be installed in workspaces designed around the equipment itself. In contrast, service robots must operate in spaces that are already used by people, such as corridors, guest rooms, stores, and hospitals.
If a robot is excessively large or its joints are too thick, it can be difficult for the robot to move through narrow passageways or work around people. Because many joints, sensors, wiring, and control devices must be arranged in a confined internal space, the size and form of the drive unit affect the overall robot design.
Especially when a robot arm or humanoid structure is used, many joints such as the shoulder, elbow, and wrist are positioned close together. If each joint becomes thick, the volume and weight of the entire arm increase, and more force may be required to move it. Making the drive unit thin and compact not only reduces the robot’s overall profile but also helps reduce the load placed on the entire structure.
Because service robots operate in close proximity to people, it is also important to ensure that their movements are smooth and stable. Not only the robot’s operating speed and path but also joint noise and vibration, as well as the response to external forces, must be considered together.
The Change in the Tasks Service Robots Perform
Key Summary As service robots increasingly lift and move objects directly, joint force and drive stability are becoming increasingly important.
Early service robots mainly focused on providing guidance through displays or carrying goods to designated locations. For such robots, a wheel-based mobility function and a sensor configuration that recognized the surrounding environment were the main design elements.
A mobile manipulator combined with a robot arm, or a humanoid service robot, can perform tasks such as grasping, lifting, and placing objects at desired positions after moving to the target location. To move even a single object, several joints corresponding to the shoulder, elbow, and wrist must move together.
As the number of joints increases, the motors, reducers, sensors, and wiring applied to each joint also increase. If the drive unit becomes large and heavy, the volume of the robot arm increases, and additional force may also be required to move the joints. It is therefore important to configure the drive unit so that the required force can be transmitted within a confined space.
A service robot does not perform just one motion but repeatedly moves, stops, and manipulates objects. During operation, the load transmitted to the joints changes depending on the object’s weight and the arm’s position, and vibration or shock occurring during movement can also be transmitted to the drive unit. For this reason, the drive system must be capable of transmitting force stably during repeated operation rather than merely providing high momentary output.
Service Robots and Reducers and Actuators
Key Summary The reducer and actuator are core components of the drive unit that convert the motor’s rotation into the force needed at robot joints and mobility devices.
A motor can rotate at high speed, but there is a limit to the amount of force it can directly generate for a robot to lift objects or move joints. The reducer helps provide the force required for the robot’s operation by reducing the motor’s rotational speed and increasing torque.
The actuator is a device that combines the components needed for motion, such as the motor and reducer. Applying an actuator to a robot joint reduces the burden of arranging and assembling each component separately and allows the drive unit to be configured according to the joint structure.
Service robots often must arrange several components in a confined space. When selecting a reducer and actuator, therefore, not only output performance but also overall dimensions, thickness, weight, wiring layout, and long-term operating conditions must be considered together.
Especially in a robot using many joints, each drive unit affects the size and weight of the entire robot. If the size of the drive unit is increased solely to provide the required force, the frame and exterior structure around the joint can also grow. Conversely, if size is reduced but sufficient force is not secured, the work range and loading capacity can be limited.
The drive unit of a service robot must therefore balance a compact profile that fits within a confined space with the force required for operation. In addition, a structure capable of withstanding repeated loads and sufficient internal space for sensors and wiring are also important design considerations.
Bonsystems’ Service Robot Drive Solutions
Key Summary For robot joints and mobility devices that must transmit force in a confined space, Bonsystems develops the BSR cycloidal reducer and the BCSA actuator.
The BSR is a reducer lineup based on a cycloidal reduction structure. It converts the motor’s fast rotation into the force needed for robot joints and drive devices and uses a structure that distributes operating loads through surface contact. In service robots that repeatedly lift and lower objects or frequently start and stop, loads are continuously transmitted to the joints and drive shafts, so a reduction mechanism capable of transmitting force stably is important.
The BSR can be applied to robots whose motors, sensors, and housings are designed separately around the reducer. Because developers can configure the drive unit to suit the robot’s joint size and structure, it can be considered when designing dedicated joints or specialized form factors. Using a hollow structure supports designs in which cables or wiring pass through the center of the joint, which is advantageous for reducing externally exposed wiring and creating a cleaner and more compact configuration around the joint.
The BCSA is an actuator that combines a frameless motor and a cycloidal reducer in a thin, compact structure. The arms and legs of a service robot must accommodate encoders, sensors, control devices, and wiring in addition to the drive unit. The BCSA’s slim structure can be used to reduce the front-to-back thickness of the joint, allowing the robot’s arms and legs to be made slimmer. When joints become thin, the design can also help reduce interference with adjacent components and secure a wider range of motion.
Bonsystems also develops Pinless cycloidal technology that reduces some of the coupling elements required in conventional pin-based configurations. The Pinless structure is intended to simplify the internal component configuration of the reducer. When the component structure is simplified, it becomes easier to fit the reducer and actuator within confined spaces and may also reduce the structural complexity of the assembly process.
Because the Pinless structure can be designed to reduce the number of parts and simplify the assembly process, it is also well suited to service robots that incorporate many joints. Because a single service robot can incorporate multiple drive units in its arms, legs, wrists, and lifting mechanisms, simplifying the structure of each joint becomes an important consideration when designing the robot’s overall assembly and production process.
The BSR and BCSA also differ in how they are applied. If the motor and housing must be configured directly to suit the robot’s structure, the drive unit can be designed around the BSR. When reducing the joint-development burden is a priority, the BCSA can be considered because it integrates the motor and reducer into a single unit. When selecting a product, a suitable configuration must be examined based on the required torque, joint size, wiring configuration, and operating environment.
Key Takeaways
As the role of service robots broadens from guidance and transport to object manipulation and motion assistance, the number of joints and drive units in a single robot is also increasing. Because they operate in spaces people use, service robots need to maintain a compact profile while providing sufficient torque at each joint for object-handling tasks.
These two requirements can conflict with each other. That is why reducer and actuator selection is treated as an early-stage design issue.
Bonsystems supports drive-unit configurations suited to different joint sizes and wiring structures through the standalone BSR reducer and the motor-integrated BCSA actuator. At the actual application stage, the product configuration must be examined based on the required torque, joint size, wiring configuration, and operating environment.
Frequently Asked Questions (FAQ)
Q1. What is a service robot?
A. It refers to a robot used to support people’s daily lives or work. It can perform various tasks such as guidance, transport, cleaning, rehabilitation assistance, and object manipulation depending on the robot’s form and role.
Q2. Where are service robots mainly used?
A. They are used in places where people live or work, such as hospitals and rehabilitation facilities, hotels, restaurants, stores, logistics spaces, and homes. The robot’s size, movement method, and required functions differ depending on the place of use.
Q3. Why is the application range of service-providing robots broadening?
A. The demand for automating repetitive transport and guidance tasks continues, and as artificial intelligence and sensor technology advance, the tasks robots can perform are also diversifying. Recently, the application range has broadened beyond mobility to include tasks that involve directly handling objects.
Q4. Why must a service robot’s drive unit be compact?
A. It must move in spaces people use, such as corridors, stores, and guest rooms. Making the drive unit compact helps reduce the robot’s overall profile and makes it easier to secure space for sensors and wiring inside the joint.
Q5. Which parts of a service robot can Bonsystems products be applied to?
A. The BSR reducer and BCSA actuator can be considered for drive units that need to transmit force, such as the arm and leg joints, mobility devices, and lifting structures of service robots. In actual applications, the product configuration must be examined based on the robot’s structure, required force, and installation space.
References
• [1] Bonsystems Official Website — https://www.bonsystems.com
• [2] International Federation of Robotics (IFR) — https://ifr.org
• [3] Korea Institute for Robot Industry Advancement (KIRIA) — https://www.kiria.org
• [4] Korea Institute of Robotics & Technology Convergence (KIRO) — https://www.kiro.re.kr
Bonsystems
A specialist in Pinless cycloidal reducers and actuators
