Tips & Guides Technical Corner - Why torque sensor, how do they work?

CloneWerks

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eBikes have one of two types of sensors that tell the bike when to actively assist.

The first is called a Cadence Sensor. It is a simple arrangement of magnets that move past a "hall-effect" sensor and indicate that the pedals are turning and how fast they are turning. However, cadence sensors do not indicate how hard you are working (pushing on the pedals) so ultimately the cadence based systems usually have more PAS (Pedal assist) settings that must be manually selected by the rider.

The second (newer, more technical) type is a Torque Sensor. Torque sensors indicate IF you are pedaling, HOW FAST you are pedaling, and HOW HARD YOU ARE PUSHING ON THE PEDALS. This gives the control computer on the bike a lot more information that it can use to auto-select assist levels, increasing and decreasing them "on demand" without any input from the rider other than pushing on the pedals resulting in far more natural feeling bike behavior.

For more details on -how- a torque sensor works see the article linked below.

E-BIKE TORQUE SENSOR TECHNOLOGY COMPARISON​

The first wave of e-bikes relied on simple cadence-based control resulting in quite unpredictable handling when cornering and during start/stop. Complementing this with a torque sensor to sense the force put into the pedals is a significant improvement. This is why the industry is chasing the ideal e-bike crank torque sensor to fulfill the requirements:
  • Low latency (max 10ms sensor delay)
  • Accurate (1-2% like a sports-bike power meter)
  • Maintenance-free
On an e-bike, the torque sensor measures the applied pedaling torque of the rider and sends it to the controller of the e-bike along with cadence information. Based on this information an algorithm controls the motor speed and power. The performance of the e-bike as perceived by the rider depends heavily on the precision and accuracy of the motor control.

As with any other system, good performance starts with good quality input signals. The torque measurement in the sensor is a key component of the input to the controller.


Read on to learn how the different technologies stack up in this game.
 
eBikes have one of two types of sensors that tell the bike when to actively assist.

The first is called a Cadence Sensor. It is a simple arrangement of magnets that move past a "hall-effect" sensor and indicate that the pedals are turning and how fast they are turning. However, cadence sensors do not indicate how hard you are working (pushing on the pedals) so ultimately the cadence based systems usually have more PAS (Pedal assist) settings that must be manually selected by the rider.

The second (newer, more technical) type is a Torque Sensor. Torque sensors indicate IF you are pedaling, HOW FAST you are pedaling, and HOW HARD YOU ARE PUSHING ON THE PEDALS. This gives the control computer on the bike a lot more information that it can use to auto-select assist levels, increasing and decreasing them "on demand" without any input from the rider other than pushing on the pedals resulting in far more natural feeling bike behavior.

For more details on -how- a torque sensor works see the article linked below.

E-BIKE TORQUE SENSOR TECHNOLOGY COMPARISON​

The first wave of e-bikes relied on simple cadence-based control resulting in quite unpredictable handling when cornering and during start/stop. Complementing this with a torque sensor to sense the force put into the pedals is a significant improvement. This is why the industry is chasing the ideal e-bike crank torque sensor to fulfill the requirements:
  • Low latency (max 10ms sensor delay)
  • Accurate (1-2% like a sports-bike power meter)
  • Maintenance-free
On an e-bike, the torque sensor measures the applied pedaling torque of the rider and sends it to the controller of the e-bike along with cadence information. Based on this information an algorithm controls the motor speed and power. The performance of the e-bike as perceived by the rider depends heavily on the precision and accuracy of the motor control.

As with any other system, good performance starts with good quality input signals. The torque measurement in the sensor is a key component of the input to the controller.


Read on to learn how the different technologies stack up in this game.
Would consider also posting this to our Resources area. I think this could be of great help to many people trying to decide cadence or torque for their e bikes.
 
Salve, ..a proposito dei sensori di coppia, avete da consigliare un modello da acquistare on-line? cerco un modello integrato nella corona che fornisca un livello di tensione 0,5V - 4,5 V. proporzionale alla forza esercitata sul pedale, ...possibilmente programmabile per i parametri principali come la sensibilità. Grazie Arthur
 
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