6-sensor technology

[Stefan Mikes]

Yes, they are positive.
(torque-a) is a typical minimum value to start any action. (a+cadence) is also a minimum value to allow instant start. There should be none or minimal effect on normal riding.

Trust me, big e-bike companies know their business. The best way to learn how it works is to demo ride a good e-bike, for example a Specialized one.

Please note that I'm only trying to learn the technology out there cause I'm shopping for a new bike lighter than my old 64lbs cruiser.
I still like to learn how the speed and accelerometer sensors are used.

The speed sensor:

• Detects the e-bike movement and allows fully controlled assistance
• Measures the e-bike speed (and distance ridden)
• Ensures the e-bike controlled by Walk Mode moves at the speed of the rider walking the e-bike.

The speed sensor is found in any e-bike, regardless of the type. It could be driven by a magnet mounted on a spoke, or on the disk brake rotor in the modern solution.

There also is the motor RPM sensor, as all the components of an advanced e-bike system must work in unison.

The role of the accelerometer is unclear to me. I'd think the sensor measures deceleration. In case the e-bike decelerates, why should it be assisted? I know how the accelerometer works in Garmin GPS bike computers: as a rapid deceleration is detected, Garmin can send an Incident Report to a trusted person. Once, my brother crashed by the Warsaw Mermaid His son got this message on the phone: "Your Dad had a crash at these coordinates [X,Y] at time xx:yy. Please take an action". Not sure how the sensor is used for the e-bike though. (Some sources read "for increased ride stability)".

 

[Neto]

Trust me, big e-bike companies know their business. The best way to learn how it works is to demo ride a good e-bike, for example a Specialized one.

Excuse me for being skeptical but I guess this is how I learn.
Shop attendant that has in depth technical knowledge of their bikes is hard to find.

 

[Stefan Mikes]

Excuse me for being skeptical but I guess this is how I learn.
Shop attendant that has in depth technical knowledge of their bikes is hard to find.

I mean, ride a proper e-bike to find out yourself.

 

[PCeBiker]

The speed sensor is found in any e-bike, regardless of the type. It could be driven by a magnet mounted on a spoke, or on the disk brake rotor in the modern solution.

There's actually sensor-less hub motors and controllers with no sensors at all.
No Hal sensors for the phase wires and no speed sensor.

Just raw power straight into the motor with the top speed limited by the battery voltage.

You only need a magnet to calculate the speed, but it isn't necessary because a simple calculation of volts × rpm per volt of the motor will calculate your speed.


They only have one Hal sensor in the throttle, but even that can be replaced with a proper twist throttle for an electric motorcycle that uses a potentiometer instead of a Hal sensor.

 

[Jeremy McCreary]

The best way to learn how it works is to demo ride a good e-bike, for example a Specialized one.

Wholeheartedly agree. The OP's been spoon-fed a lot of detailed info about the power-sensing PAS for Specialized mid-drives. Time to test-ride or rent one to see how it performs.

To my knowledge, every Specialized ebike with "Turbo" in its model name uses this PAS. On the Turbo Vado SL 5.0 with Mastermind software, you can set the TCU (built-in top-tube display) to show assist mode, instantaneous rider power, and cadence on the same page (below). Very illuminating.

Not sure how much father you'll get on the theory side. Ebike manufacturers generally don't reveal PAS details. Specialized is unusual in this regard. Online technical blurbs and articles reveal the PAS sensor array and the basic workings of their power-sensing algorithm. But they don't reveal how the cadence and wheel speed sensors are used to refine motor control. And I doubt that anyone here really knows.