Custom Tactile Sensing: Designing Touch for Complex Robotic Systems

Did you know that there are 50+ Humanoid robot companies in the world working diligently to transform how we live? In addition, there are countless other companies developing end-effectors, collaborative arms, and actuators, as well as suppliers of robotic components. In this ever-growing field of competition, collaboration, and endless possibilities, would it be reasonable that the variety of suppliers utilize the same form factor and geometries for their components? Nope!

So, let's talk about how Touchlab's custom tactile sensing can easily adapt to every surface of a robot to enhance performance and safety in their unique operating environments.

Why add touch?

If you are familiar with the Matches Experiment from Dr. Roland Johansson, you’ll note that it took roughly 5 seconds for an able-bodied candidate to grab a match from a box and light it. The same task with an anesthetized hand—without tactile touch ability—took 5x longer, as the candidate relied purely on proprioceptive and visual feedback to awkwardly pick up several matches before finally lighting one.

While a human requires re-training from their own personal norm to achieve this task, it does demonstrate the added cognitive load required when a high sensitivity and precision modality is missing to achieve dextrous manipulation tasks. Do dexterous robots move slowly not only because of actuation technology, but also due to concerns about safety and "self-hand" mutilation from clumsy interactions with the world when relying purely on vision and proprioceptive actuator sensing? Does it make sense to add processing power, and therefore power consumption, to a system to accommodate several cameras and AI systems to fill the safety and performance gap—all to gain data that is potentially low-accuracy and susceptible to occlusion?

Touchlab sensors are a perfect complement to close the data gap, enabling higher performance and system safety with lower computational and physical space requirements. Robotic systems gain immediate returns on investment with low latency (>1000 Hz) and high sensitivity (<0.1 N) contact measurements to provide immediate touch feedback that is utilized for:

1. Mitigation strategies to damaging collisions

2. Precise light-weight object manipulation

3. Enhanced features, like slip detection, for greater object control 

Similarly, sensors can provide high-force measurement (>10 N) for better control of larger contact events that systems typically encounter. All this is achieved with low power consumption (<175 mW) and data rates (<200 kbps), making the sensors a lightweight addition to any system.

The result of these quantitative benefits is that robotic systems can operate faster, more confidently, and with more strength variability—closely mimicking (and one day outperforming) human capabilities on tasks in unstructured environments.

The Path to Integrated Custom Tactile Sensing

With the value of touch established, the natural follow-on question is: “How can we add tactile sensing to our robot?”

The Touchlab Bespoke Design Package is a comprehensive, multi-step offering that tailors sensor designs to our customers' needs for every stage of development. Each step balances risk, cost, timeline, and performance to quickly and effectively produce your specific solution, utilizing our 10 years of sensor development experience in a flexible manner to meet your needs.

The first step begins with a comprehensive scoping exercise to align our engineering team with yours. In a short time, we will collect and provide guidance on your requirements for topics including, but not limited to:

1. Sensing layout and configuration

   1. Understanding the level of spatial fidelity and sensitivity required by your application

2. What environment is your system used in to help us understand:

   1. Component material requirements regarding IP rating, corrosiveness, and other wear metrics

   2. Thermal requirements for increased longevity

   3. Electrical requirements

3. Space availability for sensors:

   1. Specify the geometry of sensing surfaces and coverage expectations

   2. Locating sensing electronics

   3. Identifying integration requirements for a clean and compact solution

4. Timelines to meet your testing and sales goals:

   1. Allowing for evaluation points along the way to gain confidence on the final scalable product

5. Cost goals:

   1. Developing the right product is a balance of features and cost expectations for your product market

The results of the first phase is a detailed plan and agreement that scopes a sensor design to match your needs for any stage of development, from early R&D prototyping all the way up to million-quantity production scale.

Subsequent design steps will customize our latest, state-of-the-art sensor design to fit your most important requirements. Typically, this involves adjusting the sensing and elastomeric layer to meet the custom geometry of your hardware. 

One key differentiator of Touchlab technology is the ultra-conformable sensing sheet that can be cut, profiled, and adjusted at relative ease to meet even the most complex geometric requirements. The sensing layer has been applied to flat, dome-shaped, concave, convex, and triangular shapes, with the outline sized to fit as close as edge-to-edge with underlying hardware. Similarly, the sensing element distribution can be adjusted for various spatial resolutions required for cost and application needs.

Picture of different sheet geometries

The remaining aspects of the sensor design are configured based on the the outcome of the first step and can include, but are not limited to:

1. Collaborative design changes to customer hardware for direct and seamless integrations

   1. This can include both mechanical mounting and electrical hardware

2. Customized material development for performance requirements

   1. Elastomer formulation and development to maximize use-case effectiveness

   2. Structural material selection and manufacturing to improve durability, strength, or corrosion performance

3. Customized firmware and software changes for direct integration into the customer's control stack

4. Establish tooling and supply chain for low-cost, high-quantity parts manufacturing

5. Assembly line development for the required production scale

The final result is a solution that provides maximum capabilities at a quantity and price point to bring your robotic system performance to the next level—providing reliable tactile data for your robotics, physical AI, and teleoperation applications, for today and into a future with endless possibilities.

Inquire today about starting your bespoke design process with Touchlab!