6 axis robots reproduce the motion of a human arm by combining several joints that each move independently, and the actuator at every joint decides how steadily that motion is carried out. This article explains what an axis means in a multi-axis robot, how the motor and reducer inside an actuator work together, and why a slim actuator structure matters in robot arm design. It also introduces the Bonsystems BCSA series, a cycloidal actuator built for space-constrained joint designs.
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We perform everyday actions like picking up or moving objects without giving them much thought. Take the simple act of picking up a pen in front of you. It might look like only your fingers are involved, but in reality your wrist adjusts direction, your elbow sets the distance, and your shoulder determines the position of your entire arm. Even a task that seems this simple actually depends on multiple joints working together to create a single motion.
6 axis robots were developed based on this same structure found in the human arm. To handle the wide range of tasks required on industrial sites, such as assembly, transport, and inspection, a robot needs the ability to freely adjust its position and posture to match the object it’s working with. This need led to the development of a robot joint structure made up of multiple connected joints, much like a human arm, and this structure became the basic form of today’s 6 axis robots.
The Secret Behind Robot Arm Joints: Axes
The reason multi-axis robots can move in so many directions comes down to a structure that combines multiple joints and axes. Here, an axis refers to a joint capable of moving independently. Generally speaking, the more axes a robot has, the wider the range of motion it can achieve, allowing it to perform more complex tasks.
This operating principle is easy to understand using the human shoulder joint as an example. The shoulder allows the arm to move in many directions, whether lifting up and down or swinging forward and back. Just as the shoulder joint produces three-dimensional movement from a single joint, a 6 axis robot achieves its joint motion in a similar way, by combining axes that are each responsible for a specific direction of movement.
The key component that drives each joint is the actuator. An actuator typically consists of a motor and a reducer, with a controller added when needed. The rotational force generated by the motor is adjusted by the reducer into the torque and speed required to drive the robot joint, and the actuator then uses this output to move the joint.
Because the actuator is the component that directly drives each joint, its performance has a direct impact on the overall quality of the robot’s movement. If an actuator can’t output enough torque, the robot may struggle to hold a desired position when handling heavy parts, or it may have trouble performing consistent motions during repetitive tasks.
Driving Technology Built For 6 axis robots: The BCSA Series
For a multi-axis robot to move reliably under a variety of load conditions, it needs more than just a joint structure with a high degree of freedom. It also needs actuator technology capable of delivering sufficient torque at every joint. The BCSA series is an actuator designed to deliver strong torque in response to these requirements, and one of its key strengths is its ability to output strong torque even within a narrow internal space.
This matters especially in robot arm design, where it’s important to keep the overall size slim while still securing enough output power. If the actuator at a joint is too large, it increases the overall volume and weight of the equipment, which can limit the robot’s range of motion in environments where space around surrounding equipment is tight.
The slim structure of the BCSA makes it possible to use the internal space of a robot joint more efficiently, helping equipment be designed in a more compact form. Since 6 axis robots operate repeatedly over long periods, the weight of the equipment itself, not just the object being handled, can affect driving performance. That’s why making actuators thinner and lighter is such an important design factor for stable, long-term operation.
On top of this, the BCSA series applies a cycloidal reduction structure that distributes the load generated during operation. Because external shocks and loads are transmitted directly to the drive unit, insufficient structural stability in the actuator can lead to accumulated gear wear and eventual component damage. The cycloidal tooth profile used in the BCSA forms a surface-contact engagement, which helps reduce the load concentrated on any single point and supports consistent performance even in demanding environments with continuous shocks and loads.
Through this cycloidal technology, the BCSA V4 series supports strong structural durability, and its slim design with strong torque output makes it a driving solution suited to a wide range of space-constrained equipment, including 6 axis robots and collaborative robots.
Building on the BCSA series, Bonsystems continues to expand its driving component technology to meet the diverse needs of the robotics market. If you have questions about selecting the right actuator for a multi-axis robot joint design, or would like more detailed information about the BCSA series, please feel free to reach out through our website at any time.
F.A.Q
Q: How do 6 axis robots achieve movement similar to a human arm?
A: Multi-axis robots combine multiple joints and axes to create movement similar to a human arm. Just as a person’s joints work together to position and orient their hand when picking something up, a robot’s axes each handle rotational movement in a different direction, allowing it to move through a wide range of angles.
Q: What does an axis mean in a multi-axis robot?
A: An axis refers to a rotational joint within the robot that can move independently. A typical multi-axis robot uses several axes working together to freely adjust position and posture, enabling it to carry out tasks such as assembly, transport, and inspection.
Q: What role does the reducer play inside a robot joint actuator?
A: The reducer adjusts the rotational force produced by the motor into the torque and speed the joint actually needs. Because the joint is driven by this adjusted output rather than by the motor’s raw rotation, the reduction structure has a lot to do with how steadily a joint holds position and repeats a motion.
Q: How does actuator size affect 6 axis robot design?
A: A larger drive unit increases the overall size and weight of the equipment. This can cause interference with surrounding equipment in tight workspaces or limit the range of motion the robot is able to perform. That’s why a slim actuator structure that makes efficient use of joint space is such an important consideration in multi-axis robot design.
Q: What advantages do Bonsystems’ actuators offer for 6 axis robot design?
A: The BCSA series is an actuator designed to deliver reliable driving performance even within limited joint space, thanks to its slim structure and strong torque output. It uses an internal cycloidal reduction structure to help distribute shocks and loads generated during operation, making it worth considering for robots that require long-term repetitive work or equipment used in high-load environments.
