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Millions of people suffer globally from motor function loss due to conditions such as stroke, cerebral palsy, ageing, accidents, and other factors. This significantly limits their ability to perform even everyday tasks.

To address this issue, 21-year-old Sivasanthosh A launched the robotics startup Subtlebotic earlier this year. 

The startup’s flagship product is Limb Assist—a lightweight, external wearable motor system designed to restore limb mobility for individuals who have lost motor functions, thus allowing them to regain autonomy in daily activities.

The startup’s mission is to solve challenges using robotic technology across sectors—including healthcare, energy production and aerospace. 

“Today, we’re pioneering solutions like Limb Assist, a wearable neuro-based robotic motor technology that empowers individuals with motor impairments to regain independence,” says Sivasanthosh.

Subtlebotic is based in Sivasanthosh’s hometown of Keeramangalam in Pudukkottai district (Tamil Nadu). The idea behind starting up in a small town was to promote local innovation and provide employment opportunities to the young people of the region. 

“I wanted to prove that you don’t need to go to big cities to find innovation. I am running my company with a lofty idea to grow my city and provide employment opportunities to the youth of my town who go to work in other areas,” he says.

From a young age, Sivasanthosh had a deep fascination for science and a curiosity for understanding how things worked. His exploration with science began with projects in school, where winning various competitions fuelled his desire to innovate and solve real-world problems.  

“During the COVID-19 pandemic, I contributed by developing an automatic sanitiser sprayer and a UV germicide for local hospitals. Alongside this, I was working on satellite technology and researching solid-fuel rockets, testing my projects right in my hometown,” says the young entrepreneur. 

This hands-on experience laid the foundation for his professional growth, which was further solidified by practical exposure at the National Centre for Combustion Research and Development at IIT Madras when he was just 18 years old.

Sivasanthosh, who has completed his diploma in mechatronics engineering, is currently pursuing a BE degree in aerospace engineering at KCG College of Technology, Anna University, Chennai. He is in his final year and will be graduating soon. His college has granted him permission to dedicate most of his time to his startup.

Using robotic technology to improve quality of life

Limb Assist is designed to benefit individuals facing motor impairments caused by stroke, spinal cord injuries, cerebral palsy, Parkinson’s disease, and traumatic Injuries. It focuses on providing support to the fingers for fine motor functions such as gripping, holding, and manipulating objects. 

Using Limb Assist, users can grip objects, such as cups, plates, tools, and bags, hold and carry them. Limb Assists also helps with typing, writing, buttoning clothes and fastening zippers. 

For users with limited control over finger movements, the device enhances precision by amplifying residual signals (which utilise neural signals, such as electrical impulses from the body, to drive robotic actions) and executing intended actions like gripping or typing. 

For those who are unable to move their fingers entirely, Limb Assist interprets brain signals or alternate nerve pathways, enabling robotic-assisted finger movements for tasks such as holding objects, writing, and operating devices.

“Our sensor technology is developed using advanced systems like EEG (electroencephalography), EOG (electrooculography), and BCI (brain-computer interface),” he adds

Electroencephalography measures electrical activity in the brain and records it as a visual trace, while  electrooculography measures the electrical potential between the cornea and the retina in the eye. Brain-computer interface is technology that lets a person control an external device using their brain signals. 

Potential users of Limb Assist include individuals with motor impairment and elderly individuals. 

“The dual-action capability (upward and downward movement) ensures seamless performance in everyday functions, restoring independence and improving quality of life,” explains the founder.

“We will use our technology to create every motor system for humans in the future,” he adds. 

The startup is also developing  multi-axis wind turbines and eco-friendly batteries for energy production and storage and nano robots and robotic arms for application in healthcare and space exploration. These products are currently in the R&D stage.

Business model and way ahead

Limb Assist is currently undergoing pilot testing and has not yet been officially launched. Subtebotic is gearing up for the commercial launch of Limb Assist within 6 to 12 months, at a price of Rs 35,000 to Rs 45,000. 

“Our focus is on gathering user feedback to perfect the product before full-scale commercialisation. Currently, our focus is on prototype development and pilot testing,” says Sivasanthosh.

Subtlebotic will sell Limb Assist to healthcare providers, rehabilitation centres, and clinics specialising in physical therapy. It also plans to enter into collaborations with government entities to ensure public access to the device through government-supported health plans. The device can also be leased by hospitals and clinics, making it affordable for patients through subsidised or insured models. 

The startup has raised a total of Rs 14 lakh through grants, competitions, and prize money from innovation competitions and awards. It is exploring pre-seed funding to scale its operations and bring its products to the market.

Going forward, Subtebotic aims to extend Limb Assist’s capabilities to multiple body parts such as the arm, legs, neck, shoulder and hip. 

“Our ultimate vision is to develop a full-body assistive system powered by brain-computer interface technology, which will interpret neural signals to restore motor functions,” says the entrepreneur.

Limb Assist competes with the products of companies such as Exo-Bionics, ReWalk Robotics (rehabilitation systems) and Penumbra Inc (VR-based system).

Commenting on Subtlebotic’s differentiation in the market, Sivasanthosh says, “Subtlebotic combines neuro-based robotics with adjustable mechanisms, allowing the device to be adapted to different users’ needs and sizes. The system is designed for intuitive control, making it easy for users to operate and move the device naturally. 

“Our technology integrates seamlessly with the user’s own neural signals, providing a unique, responsive experience that is not currently available in traditional rehabilitation or exoskeleton devices.”

Meanwhile, the startup is also working on advancements to its multi-axis wind turbine with integrated solar cells and improving overall efficiency and reliability. It is also enhancing the turbine’s capacity to capture wind from all directions at low speeds. 

“This hybrid solution will help in harnessing both wind and solar energy for sustainable power generation. It will serve as a critical supply of backup power for homes and businesses during peak demand periods or emergencies,” explains the founder.

Subtlebotic was part of YourStory’s Tech30 cohort of promising startups of 2024.