Redundant Accelerator System

Disambiguation

The term 'throttle' originates from gas/combustion engines, where it refers to a control element for acceleration. As we transition to electric vehicles, we prefer the term 'accelerator'. Both terms can be used interchangeably as synonyms.

Two redundancy options available for enhanced Ride-by-Wire safety:

• Dual analog signal accelerator
• Single analog signal with end-stop switch

Either configuration sets sig_acc to NaN on error, triggering vehicle disarm. Recovery behavior controlled by safetyopts parameter - default setting maintains disarm until power cycle.

info

Parameters located in /acc folder

tip

Test system with single accelerator before implementing redundancy to isolate potential issues.

Configuration Parameter

dual_err

• 0:1 - Error threshold for dual analog signals
• -1 - Enables end-stop switch monitoring

Dual Analog Implementation

Compares primary and secondary accelerator signals (post-ASC processing). Disables acceleration if signal difference exceeds dual_err threshold.

Setup Process

1. Configure inputs:
   • Set /io/IN_acc: GPIO ID for primary signal
   • Set /io/IN_acc_2: GPIO ID for secondary signal
2. Monitor via Scope: /acc/asc/out, /acc/asc_2/out, /acc/acc_err
3. Adjust ASC values for signal matching (minimize acc_err)
4. Set dual_err slightly above maximum observed acc_err

End-Stop Switch Implementation

Monitors single analog signal with end-stop switch. Disarms if accelerator value exceeds dual_err when end-stop activated.

Setup Process

warning

Note distinction between GPIO ID and GDIN ID

1. Configure inputs:
   • Set /io/IN_acc: GPIO ID for accelerator
   • Set /io/IN_acc_2: GDIN ID for end-stop
2. Monitor via Scope: /acc/asc/out, /acc/acc_err
3. Note /acc/asc/out value at end-stop activation
4. Set dual_err to negative of noted value
5. Verify acc_err remains zero during operation

Input ID Reference

See Input mapping for details.

GPIO ID	Input
8 (default)	GPIO0
9	GPIO1
10	GPIO2
11	GPIO3
12	GPIO4

warning

Configure GPIO as floating input: set /common/ioconfX to 0. GPIO details

GDIN ID	Input	Type
16	GDIN0
17	GDIN1
18	GDIN2
19	GDIN3
20	GDIN4
32	DIN1	uint8
33	DIN2	uint8
...	...
39	DIN8	uint8

tip

• End-stop compatible with GDIN or DIN
• Enable pull-up for end-stop: set /common/ioconfX to 1. GPIO details