Dual Valve Muscle

From Merlin Systems Wiki

The Merlin Dual Valve Muscle is the latest development of the Merlin air-muscle, based on our 'Smart valve' technology.

(click for hi-res version)

By using two independent control valves, the muscle can hold a given position without constant air usage. Because the control valves are proportional, a smooth control can be achieved, allowing very precise variations in output force/position.

Basic features and advantages -

high power-to-weight ratio
proportional operation
flexible, non-rigid installation
force compliant output
airflow controlled
electrically operated

These are the muscles used in our Robot Arm -

For a simpler and cheaper actuator, see Leaky Muscle.

Air muscles are often used in quite large groups to control complex mechanical structures. To control multiple leaky muscles, see the MDB Muscle Controller.

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Movies

(N.B. in Quicktime format)

-- Showing muscle contraction expansion
N.B. as it is loose on the bench (unloaded), you don't see it fully stretched
(so not full movement) -
valve muscle/Muscle UpDown.MOV Muscle UpDown.MOV (4.4Mb)

-- Showing 2 muscles in antagonistic operation, in the Robot Arm -
arm/Forearm Movement.MOV Forearm Movement.MOV (6.4Mb)

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Product Details

Basic parameters (standard reference build: 30cm 'active' length, 3cm maximum diameter) -

inlet pressure: up to 6 bar
movement level: 10cm maximum
force level: 10KgF/bar at full extension
force withstand: 40KgF maximum
inlet connection: typically M8 thread / 4mm airline (see MAV Proportional Air Valve for options)
drive level: current controlled, up to 1A

The basic muscle is approximately 30cm long with a 30mm maximum diameter. This produces forces of up to about 10KgF/bar, and about 7cm maximum movement.
(N.B. force achieved depends on movement level, reducing to zero at full contraction)

Movement is proportional to 'active length', which can be specified as required: The only tradeoff is a slower response rate.
Different force levels can be achieved with a different braid widths: Approximately double- and half-strength muscles can be produced to order (options: 20 and 40mm diameter)

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