slomobile
New member
Does this thing exist? I'd like a link to ANY example, preferably one currently for sale.
It would be a single item that can be mounted on either left or right handlebar. Or in my case, one on each side.
It should come to rest in a roughly middle position (balanced spring tension), so that it can be twisted either forward or back. It would need a mechanical trim mechanism to bias the resting position toward either extreme. Similar to the way a throttle trim on a boat or RC car gives you more control authority in the forward direction than in reverse.
Ideally, one could swap in stiffer or weaker rate springs in either twist direction. So that each hand's forward twist is a weak long travel, while each hand's reverse twist is a strong short travel.
My application is an E quad for quads. For those without sufficient arm strength or range of motion to steer with handle bars, but still having handlebars.
The rear wheels would be typical fixed position differential steer. Modeled like any differential steer robot. The front wheels are also differential steer on a long trail pivot axle. Pivot point well in front of the axle so that small differences in front wheel velocity result in rapid change of direction of the vehicle nose. Very "twitchy" steering by design. The handle bars can be connected to the pivot axle via adjustable ratio so that the full wheel steering angle can be tuned to whatever handlebar angle is achievable by the individual driver.
Differential steering is typically controlled via a joystick. Indeed, this vehicle will also have a joystick on a long coiled cord. So that it may be driven and parked by a person walking alongside, or riding on the rear seat, or by the primary driver if handlebar steering becomes too much for them while on the trail.
I'd be happy to work with someone that thinks they are capable of developing the ambidextrous reversing twist grip throttle.
And since this is the controllers and programming forum, I could use some help modeling forward and reverse kinematics. How the 4 wheel speeds map to pivot axle angle and overall vehicle movement with configuration variables of
distance between wheels
trail (distance between front axle pivot projected on the ground, and front wheel contact line) currently about 10" but working on making that adjustable.
caster (currently 0)
camber (currently 0)
toe (currently 0)
and dynamic variables of individual L/R throttle input mapping to different wheels speeds when traveling above a certain threshold to prevent barrel rolling from excessive twitchy steering. Probably assisted with yaw rate sensor, steering angle sensor, 4 wheel speed sensors. Maybe a suspension droop sensor to distinguish terrain slopes from speed induced roll and pitch. Optimizing for lowest current during smallest possible turning circle. If a complicated multi step turn in place strategy proves optimal, automate that for 90 and 180 turns.
slomobile
Dustin Maki
It would be a single item that can be mounted on either left or right handlebar. Or in my case, one on each side.
It should come to rest in a roughly middle position (balanced spring tension), so that it can be twisted either forward or back. It would need a mechanical trim mechanism to bias the resting position toward either extreme. Similar to the way a throttle trim on a boat or RC car gives you more control authority in the forward direction than in reverse.
Ideally, one could swap in stiffer or weaker rate springs in either twist direction. So that each hand's forward twist is a weak long travel, while each hand's reverse twist is a strong short travel.
My application is an E quad for quads. For those without sufficient arm strength or range of motion to steer with handle bars, but still having handlebars.
The rear wheels would be typical fixed position differential steer. Modeled like any differential steer robot. The front wheels are also differential steer on a long trail pivot axle. Pivot point well in front of the axle so that small differences in front wheel velocity result in rapid change of direction of the vehicle nose. Very "twitchy" steering by design. The handle bars can be connected to the pivot axle via adjustable ratio so that the full wheel steering angle can be tuned to whatever handlebar angle is achievable by the individual driver.
Differential steering is typically controlled via a joystick. Indeed, this vehicle will also have a joystick on a long coiled cord. So that it may be driven and parked by a person walking alongside, or riding on the rear seat, or by the primary driver if handlebar steering becomes too much for them while on the trail.
I'd be happy to work with someone that thinks they are capable of developing the ambidextrous reversing twist grip throttle.
And since this is the controllers and programming forum, I could use some help modeling forward and reverse kinematics. How the 4 wheel speeds map to pivot axle angle and overall vehicle movement with configuration variables of
distance between wheels
trail (distance between front axle pivot projected on the ground, and front wheel contact line) currently about 10" but working on making that adjustable.
caster (currently 0)
camber (currently 0)
toe (currently 0)
and dynamic variables of individual L/R throttle input mapping to different wheels speeds when traveling above a certain threshold to prevent barrel rolling from excessive twitchy steering. Probably assisted with yaw rate sensor, steering angle sensor, 4 wheel speed sensors. Maybe a suspension droop sensor to distinguish terrain slopes from speed induced roll and pitch. Optimizing for lowest current during smallest possible turning circle. If a complicated multi step turn in place strategy proves optimal, automate that for 90 and 180 turns.
slomobile
Dustin Maki
