The normal ride mode

The basic principle of the firmware is the relationship
_Motor power = assistance factor * human power _

Mechanical power is speed * torque

For the motor, this means:
_Motor power = rotor speed * motor torque _

For human power, this means:
_Human power = cadence * torque at the crank _

So we can write:
_Rotor speed * motor torque = assistance factor * cadence * torque at the crank _

With a middrive motor, the rotor speed is always in a constant ratio to the cadence due to the internal gear Motor speed = gear ratio * cadence

Therefore, the cadence cancels out of the equation.

_Gear ratio * Cadence * Motor torque = Assistance factor * Cadence * Torque at the crank _

Solving for torque yields:
_Motor torque = Assistance factor * Torque at the crank / Gear ratio _

The motor torque depends solely on the motor current and the motor constant K_M.
_Motor torque = Motor current * K_M _

It follows that: _Motor current = Assistance factor * Torque at the crank / (Gear ratio * K_M) _

The various constants in the formula can be combined into a single constant:

Motor current = System constant * Assistance factor * Torque at the crank

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