Can “Soft Robotics” Unlock a New Frontier for Rigid Robotic Arms?

Humanity’s desire to replace manual labor with machines is nothing new—and every so often, a breakthrough rekindles that dream. This year, humanoid robots launched by companies like Tesla and Xiaomi have reignited attention in the robotics industry.

However, the harsh reality remains: before machines can fully replace humans, extensive human-machine collaboration must be achieved. Today’s robotics landscape is still largely stuck in a period with few breakthrough products or disruptive technologies.

Take robotic arms—one of the longest-standing and most widely applied technologies—as an example. Whether it’s traditional industrial arms or the newer collaborative types, the core goals remain speed and precision for manufacturing. But as applications involving close physical interaction with humans increase, the demand is shifting toward safety.

With the industrial sector reaching saturation, the robotic arm market needs new growth opportunities.

Imagine a robotic arm that’s not only flexible and safe, but also supports interactive control. Such a design breaks the boundaries of traditional industrial use and opens doors to service industries and beyond.

A new generation of robotic arms has emerged to meet this demand—featuring soft, compliant structures and intelligent control. These systems come in various configurations, such as versions with bending joints, telescopic joints, and hybrid rigid-flexible designs. These new forms are built on disruptive innovations in material science, structure, and actuation.

Behind this evolution is a long-term belief in deep tech and robotics. The focus has shifted toward visionary teams and original technologies capable of reshaping core robotic systems from the ground up.

Unlike conventional robotic arms, these new soft arms resemble elephant trunks in appearance—flexible, organic, and agile. This biomimetic approach represents a major departure from rigid, motor-driven joints.

The key innovation lies in the system’s foundational design. Instead of rigid mechanical joints driven by motors and gear reducers, the new arms use arrays of flexible "muscle" joints formed from soft materials. These are powered by fluid-based actuators, known as SlimDrive systems, offering superior compliance and adaptability.

These soft actuators are derived from microfluidic technologies and use precision air pressure control to drive movements. Each flexible joint typically consists of 3 to 6 soft actuators—an optimized structure for three-dimensional motion while minimizing material cost.

Inside the arm, pressurized air flows through interconnected tubes into the soft actuators, expanding or contracting to control movement. By varying the air pressure in each actuator, the arm can achieve precise and smooth directional changes.

This design enables safe operation in complex settings, including human-machine interaction, confined spaces, and obstacle-rich environments. It’s particularly valuable for tasks requiring delicate touch, like interacting with fragile or sensitive objects.

At the control level, algorithms still resemble those of traditional arms—tracking the motion at the tip and calculating reverse kinematics for each joint. However, the increased degrees of freedom and material nonlinearity add complexity to motion planning, requiring new approaches to achieve optimal control.

The biggest challenge in soft robotics lies in rethinking the entire system architecture. Since everything—from materials to motion control—is fundamentally different, there’s no off-the-shelf open-source solution to replicate.

But that’s also what gives these systems their distinct advantages:

Unprecedented Flexibility:

Soft arms can achieve six degrees of freedom like traditional rigid arms. But with added internal degrees of freedom from actuator redundancy, they can perform complex maneuvers in tight spaces, avoid obstacles more effectively, and reduce spatial requirements.

Enhanced Safety in Human-Machine Interaction:

Traditional collaborative arms rely on sensors and vision systems to ensure safety. But when these fail, the inherent rigidity and inertia can still cause harm. Soft arms, in contrast, are inherently safer—lighter in weight, more compliant, and driven by compressible fluids that absorb impacts.

Lightweight Yet High Load Capacity:

Weight is often a limiting factor in mobile and service robots. Soft arms break that trade-off, offering a payload-to-weight ratio of up to 3:1. For example, a 3 kg soft arm can handle loads over 10 kg, thanks to the high elasticity of the actuators and the use of compressed air rather than heavy motors.

Better Cost Performance:

Because of their structural simplicity, soft arms eliminate many of the most expensive components in traditional arms—like motors, gearboxes, and controllers, which together account for over 70% of the total cost in many robotic systems. The result is a high-performance solution with a more efficient and scalable supply chain.

One promising deployment of soft robotic arms is their integration with drones. Traditional robotic arms are hard to mount on UAVs due to weight and rigidity. But soft arms can be designed to meet stringent space and flexibility requirements, enabling aerial manipulation, remote pickup, object delivery, and inspection.

In inspection tasks, they help prevent issues like jamming doors, navigating tight equipment spaces, and conducting safe contact operations. Beyond UAVs, soft arms will also be integrated into mobile ground robots (e.g., AGVs/AMRs), paving the way for new classes of compound intelligent systems.

In the service sector, the future is even more promising. With low cost, lightweight design, safe human interaction, and fast deployment, soft robotic arms aren’t here to replace traditional ones—but to complement them. While rigid arms will continue to dominate heavy-duty industrial applications, soft arms are poised to open up a new blue ocean in emerging fields like caregiving, logistics, education, and home services.