Dynamic Pressure Plate Technology

What is a ‘High speed, high resolution 2D dynamic pressure measurement plate’?

High resolution

A pressure plate is a thin plate containing thousands of pressure sensors. Our off-the shelve available plates contain almost 4 sensors per cm2. Our 0.5m plate contains 4096 sensors, while a plate of 1m contains 8192 sensors.

2D (or 2-dimensional)

The sensors are typically arranged in a 2-dimensional matrix (square, rectangular, but can be circular too). Typical arrangements are 64 x 64 sensors (0.5m plate), or 128 x 64 (1m plate).

High speed

The entire sensor matrix is being scanned by electronics, up to a few hundred frames per second. Thanks to our patented scanning method, we can achieve very high frame rates over a large surface. The result is a ‘high-speed film’ of the pressure distribution on the contact surface between a subject and the plate. The plate actually ‘films’ the pressure distribution at a rate of a few hundreds of images per second, comparable with basic high speed cameras. The data is sent over USB to a computer, where it can be visualized, analyzed and interpreted.

Dynamic

While a typical balance gives you your precise weight after a few seconds of averaging, a high speed pressure plate gives you the pressure distribution at a speed of a few hundred values per second. You’re actually looking at thousands of very small weight balances, each measuring the pressure exerted on them.

A short physics refreshment : the relationship between pressure, force and weight (mass)

Since there is a simple relationship between force and pressure, a pressure plate is sometimes confused with a ‘force plate’ :

                                        Pressure = Force / Surface     (units : 1 Pa = 1 N / m2)

You can also derive mass (or weight) from the pressure data, as you’ll probably also remember from physics classes, that :

                                        Force = mass x g               (units : 1N = 1kg x 9.81m/s2)

So is it a force plate?

A force plate is very different from a pressure plate. Most scientific force plates output 6 signals,  force and momentum, each in 3 dimensions (Fx, Fy, Fz and Mx, My, Mz).

A pressure plate outputs thousands of values, one for each sensor. However, a pressure plate cannot distinguish between forces, moments, and X, Y and Z, and simply ‘sums’ these values to pressure exerted on each of the individual sensors.

Force and pressure plates each have their own applications, and are in fact very complementary.
Therefore scientific applications often combine a force plate with a pressure plate, to have the best of both worlds.

So is it a balance scale?

Yes in some way, but … everything in physics comes with a price – what you win on one side, you lose in the other.  

The measured values are less precise than the one obtained from a balance scale. But in return for that, instead of 1 single sensor that outputs averaged data every few seconds, you look at thousands of small sensors, as well as a frame rate which is roughly a 1000 times higher. This allows to analyze physical and mechanical processes (like centre of pressure movement) which cannot be visualized by any other equipment, not even X-ray or MRI scanners.