Pedal Assist System

Lynx offers an advanced pedal assistant system with cadence and torque input with the possibility.

warning

• From LYNX 5.x.x the PAS system is completely reworked. The old parameters are not compatible with the new system. You must tune the new parameters to achieve the desired behavior.

Digital pulses from cadence input are normalized in the Tachopas block and its output is read as cadence [RPS]. Torque input is normalized in the ASC block and its output is normalized as sig_torque [0-1]. Than the is done compotation on the cadence and sig_torque and the output is multiplied by the paslvl variable. Than it goes to the cscpas block where the output is shaped to the desired sig_pas [0-1] signal. The signal is mapped to driver current mode.

PAS signal flow:

How to setup the PAS

1. Start with map where the paslvl is set to 1.0. This means that the PAS signal is not modified and it is in full power.
2. Set the IN_cadence and IN_torque to the correct input pins. More about imput mapping
3. Tune the tachopas block to get clean cadence signal. Usually just set the ppr to the number of magnets on the cadence sensor.
4. Tune the asctorque block to get 1 at full pedaling force.
5. Tune the cscpas block to get the desired PAS feel. Usually tune the low deadzone ldz to get PAS assist at right time, and the lpf to smooth the signal.
6. Tune the paslvl to get the desired torque output for each power map.

info

• If you have only cadence sensor, leave the IN_torque to 0. And do not use the asctorque block. The sig_torque will be 1 all the times.

Variables

info

• The mentioned variables are located in the folder /pas.
• If you do not see pas folder in the parameters folder, your controller does not have PAS support. Check FW modification for more info

Parameter	Description
pasopts	1 - Enables reverse pedaling brake (PAS brake)
asctorque	ASC block for torque
tachopas	Tachopas block for cadence input
cscpas	CSC block for PAS signal shaping

State variable	Description
paslvl	Indicates actual value of paslvl multimplier (this changes with maps)

Cooperation with other modes

• PAS and throttle seamlesly cooperate with throttle. Which input is higher, that mode is active.
• If there is sig_acc negative (reversing), PAS is disabled.
• Brake, seatswitch has higher priority than PAS.