Force Measurement

In physics, a force is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape. The SI unit (International System of Units) for Force Measurement is the newton. This is the force required to accelerate a one kilogram mass at a rate of one meter per second squared. The corresponding CGS Force Measurement unit is the dyne, the force required to accelerate a one gram mass by one centimeter per second squared. The English unit of Force Measurement is the pound-force, which is defined as the force exerted by gravity on a pound-mass.

Force sensing resistors are commonly used for Force Measurement. A force sensing resistor is an electronic device whose resistance changes when a force or pressure is applied to it. Generally, force sensing resistors are constructed from two film layers that are assembled together. A resistive material is coated on one film layer, and an electronic circuit is coated on the second film layer. These two layers are joined with a bonding agent. The circuit resistance is quite high in the absence of force. However, the resistance drops when force is applied to the sensor. This drop is caused by the resistive material being pressed together and against the circuit. The resistance drop is proportional to the amount of force being applied. Consult the Application Glossary for additional information on force sensing resistors.

The Tactilus® Free Form sensor system is a user constructed Force Measurement system that provides unprecedented flexibility and ease of use. The Free Form philosophy empowers the user to select the precise location for data collection. Sensors are disposable and very economic. Various sensors and the data collection hub are shown in Figures 1 and 2.



sensor shapes
Fig 1: Various Sensor Shapes and Sizes
Fig 2: Tactilus® Data Collection Hub with 8 Sensor Elements Connected
Fig 2: Tactilus® Data Collection Hub with 8 Sensor Elements Connected

Designed for multi-axis or curvaceous topographies, the Tactilus® Free Form Force Measurement system provides engineers the capability to collect and assimilate data from up to 32 separate sensor elements simultaneously at desired locations. Unique to the industry, each Free Form sensor element is individually calibrated sequentially serialized, and quality tested to ensure the highest repeatability and accuracy. In addition, sensor assemblies feature ergonomic and high quality Berg connectors, ensuring durable interconnection.