The motor will assist on uphill but brake on downhill.
Official Website
No English though 
https://www.yamaha-motor.co.jp/wheelchair/lineup/swing/
https://www.yamaha-motor.co.jp/wheelchair/ambassador-report/003/

Official Website
https://www.yamaha-motor.co.jp/wheelchair/lineup/swing/
https://www.yamaha-motor.co.jp/wheelchair/ambassador-report/003/


