Precision gears made of Stanyl®, a high-performance polyamide 46 (PA46) resin
from DSM Engineering Plastics, help a new joystick-based drive-by-wire system
translate a driver’s steering movements into vehicle control. Called
Joysteer®, the new system was designed to enable drivers with arm muscle
disabilities get behind the wheel – or in this case, joystick – and drive by
themselves. Joysteer will be demonstrated at Hannover Messe 2006, 24-28 April,
a leading showplace for mechanical and plant engineering, electrical
engineering, electronics and the automotive sector.
Developed at the highly-regarded Bern University for Applied Sciences
HTI-Biel, Joysteer, augments a car’s conventional steering wheel with a pair
of joysticks mounted on either side of the wheel. These are electronically
coupled to the vehicle’s steering mechanism. At Hannover Messe, Joysteer will
be demonstrated in a Volkswagen T5 Multivan, donated by the automaker, at
Stand A28, hall 2.
Developed in close cooperation with the school’s design team and with the
fabricator of the gears, Mikron Plastics Technology, the Stanyl gears play
important roles both at the joystick and at the vehicle’s steering shaft. The
application runs the gamut of performance from delicate to tough, with both
applications depending on Stanyl’s dimensional stability, low friction, and
ability to absorb vibration and noise.
Said Hans Wennekes, Business Development Manager, Stanyl, “The gear sets in
both the joysticks and the motor drives are zero backlash. That’s the only way
the joystick can deliver absolute precision for encoding, and it enables the
tightest possible steering control, without wander. Technical collaboration
between DSM, Mikron and HTI Biel – or, if you will, the material maker, the
gear cutter and the design team – was the only way such a precise mechanism
could have been developed.”
The joystick gears must precisely translate small movements to programmable
encoder circuitry. The movement required is small, and the touch must remain
light. The steering shaft gears, on the other hand, must apply strong forces
to the vehicle’s steering system, calling on Stanyl’s resistance to fatigue
and mechanical stiffness and strength.
A critical innovation in the design is feedback to the driver. Small motors in
the joystick mechanism provide variable resistance that is sent back to the
driver through the Stanyl joystick gears. This resistance signals the severity
of the turn and also transmits the road feel of bumps and surfaces to the
driver. This enables the system to give drivers the same kinds of tactile
information a driver would sense while using a conventional steering wheel.
The degree of feedback can be programmed for a given driver’s muscle
capabilities.
At HTI Biel, a team of employees and faculty, backed by a close-knit group of
industry sponsors and participants, has worked over the last four years to
perfect Joysteer. The technology won the Swiss Technology Award 2006. Key
development members have founded a new, spin-off company, also called
Joysteer. A broad range of sponsors and advisors, including automotive
manufacturers as well as associations and foundations for the disabled, have
provided important support from the start.
