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Tunneling ball device - Low Latency Mechatronics

A steel ball through a spinning hole, every time

Our Low Latency Mechatronics project. QBayLogic’s hard real-time control design for the tunneling ball device, built in Clash with CAES at the University of Twente.

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The challenge

In cyber-physical systems, timing is everything. Controllers must deliver results within strict deadlines, so the design needs predictable delays. The tunneling ball device makes that requirement visible.
- Observation: two sensors (b) and (c) watch a spinning disc (e) and the trajectory of the falling balls.
- Prediction: the device works out precisely when a ball (d) will reach the disc.
- Physical control: a motor (f) drives a disc with two holes in it. The disc is what steers the balls.
- Feedback loop: the motor and rotary sensor feed position data back, so the controller corrects the disc’s trajectory continuously.
The balls fall only a few decimetres. In that window the controller has to predict each arrival and rotate a hole into place. That demands high-speed, hard real-time control.
Miss the deadline by a millisecond and the ball hits the disc instead of the hole. Nothing degrades gracefully. Computation and physics have to agree, exactly, every time.

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The approach

We designed the controller in Clash with the CAES group at the University of Twente. Clash describes the hardware, so the design and its specification stay in one language.
That let us build the controller incrementally. We verified behaviour and properties at each stage, instead of waiting for a finished design to test.
Clash also gave us advanced parameterisation and compile-time computation. So we reused code across variants without paying for it in performance.

The results

The device runs the loop in hard real time, fast enough to place a hole under a falling ball.
The hardware that shipped is a refinement of the original code, not a re-implementation of it.
Because we verified every stage as we went, the finished controller behaves the way the specification said it would.

This project showcased Clash’s remarkable aptness for designing control systems in cyber-physical environments.

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More information?

Christiaan Baaij, PhD

Call me on +31 (0)6 1602 2536

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Why QBayLogic?

QBayLogic brought a unique tool to the table: Clash, a hardware description language. Clash is more than code; it’s a powerful tool for driving innovation. It allows for incremental development, testing as a computer program, and smooth transitions to functional hardware designs. What sets our approach apart is that the final hardware product is a refined version of the original code, not a mere re-implementation.

This project exemplifies our commitment to pushing the boundaries of what is possible in the realm of cyber-physical systems. Applications where the applied expertise would also fit:

Quality assurance: defect detection and sorting
Laser evaporation of droplets
Advanced driver assistance systems (ADAS)