IMPLEMENTATION OF OPEN-FLOW AND CRANE TIP
TRAJECTORY CONTROL
Vertical translation
SIMULATION MODEL
Horizontal translation
Boom
Jib
Telescope head
Telescope cylinder
Jib cylinder
A simulation model have been created to visualize control
strategies and to verify their functions before implementation
on the crane. The simulation model has strived to get realistic
properties and geometries so that the model behaviour is very
similar to the real crane by measurements and testing.
Mast
Telescope body
Boom cylinder
The mechanics in the simulation model
OPEN-FLOW
Open flow is a displacement controlled system which means that
the operator controls both the valve and the pump, at the same
time when operating the joysticks. Every joystick signal
represents a flow and when all flow demands is known you can
calculated which pump flow you have to deliver. This required
flow is then converted to a rotational speed of the motor which
drives the pump with fixed displacement so that the right amount
of flow is delivered as:
qP=εPDPnPηvol,p
M
Open-flow system with fixed pump controlled by a variable motor
and anti saturation compensators
CTTC
It has been implemented a crane tip trajectory control, CTTC,
on the crane. CTTC means that a joystick movement
corresponds to a movement in a horizontal or vertical direction
of the crane tip. This means that the crane have to use several
functions simultaneously. A big challenge with this is that no
position sensors are used. This means that every position have
to be calculated exactly by using a calculated flow through each
valve from the pump to the cylinder. The CTTC is aimed to be
used mainly for inexperienced users.
Nils Heinerud
Isak Demir
Henrik Gustafsson
Erik Forzelius
Mikael Uddnäs
Jonas Hjälte
Division of Fluid and Mechatronic Systems
Autumn 2010