Martin Lukac » fabrication

Ant capsule

martin.lukac@iaac.net — Mon, 17 Jun 2013 19:18:25 +0000

The final object installment. Two acrylic capsules interconnected, one containing ant colony, other one with a series of capacitor membranes forming an electric field when being actuated. Rather than an ant habitat model, this is an encapsulated experience for ant species attracted to electric fields. Sound sensor could actuate the capacitors based on the activity of ants. The system could detect ant activity and regulate the intensity of electric field and thus influence the behavior of ants.

Another day, another actuation test

martin.lukac@iaac.net — Thu, 13 Jun 2013 13:17:16 +0000

Another actuation testing, this time using a different shape. Two shapes are connected to each other, one is just a stretched membrane without the powder, the other one is complete capacitor. Actuation starts around 1.4 kV. Breaking point should be around 6.5 kV. Finally one capacitor that remained intact after testing.

Actuation tests

martin.lukac@iaac.net — Wed, 12 Jun 2013 15:10:42 +0000

Testing the actuation with high voltage electricity and material properties of the membranes at the same time. Membranes appear to be very sensitive to voltage above 4kV. They tend to damage quite easily. Actuation usually starts around 1.3 / 1.5 kV. Discharging capacitor and converter is done manually, via bleeder resistors board. Capacitor should store electric charge after it is switched off for certain time. After that moment it should discharge gradually and the time of discharge should be influenced by outer level of humidity and the conductivity of the capacitor itself. This could be an interesting moment in the behavior of an array of capacitors being switched on and off.

test object

membrane elasticity testing

Polymer actuation test 1.0

martin.lukac@iaac.net — Fri, 07 Jun 2013 18:41:32 +0000

Testing the actuation of the polymer film. Materials and electronics: VHB polymer film, conductive graphite powder, acrylic glass, high voltage converter, variable power supply, cables.

Electroactive polymer membrane test

martin.lukac@iaac.net — Thu, 06 Jun 2013 13:46:34 +0000

Testing the elasticity of VHB polymer film membranes attached to the planar surface. This method could be applied to the system of polymer actuators inside the final object prototype.

D.I.Y. electroactive polymers / high voltage test circuit

martin.lukac@iaac.net — Mon, 20 May 2013 14:36:28 +0000

An electronic test circuit for electroactive polymer actuator. The aim of this circuit is to test the possibility of controlling the polymer actuator with a microcontroller (Arduino). The circuit consits of 3 blocks 1) Variable power supply – provides stable voltage 0-12V and current of 125 mA for the high voltage converter. 2) High voltage converter and polymer actuator – converter converts incoming voltage of 0-12V and transforms it to high voltage (0-6kV). High voltage is essential for actuation of polymer. Graphite cathode and anode start to actuate the polymer matter around 2 kV. Positive and negative output of the converter are directly connected to the anode and cathode of the actuator. Bleeder resistors discharge the electric charge after the circuit is off. 3) Arduino microcontroller and digital potentiometer MCP4131 – control the behaviour of the actuator. Digital potentiometer has a range of 128 values. It is possible to add sensors to this circuit.

digital potentiometer MCP4131 test circuit variable power supply test circuit

variable power supply test circuit

D.I.Y. electroactive polymers / scissor mechanism

martin.lukac@iaac.net — Mon, 20 May 2013 13:47:28 +0000

Mechanism for prestretching the VHB films. Film is being applied to the mechanism, stretched in each direction and then fixed to the stable frame.

D.I.Y. electroactive polymers | intro

martin.lukac@iaac.net — Sun, 19 May 2013 13:26:25 +0000

Electroactive polymers (EAP) when stimulated by an electric field, these polymers exhibit a change in size and shape. Can be used as actuators or sensors. Diaelectric elastomers are material systems producing large strains. They transform electric energy into mechanical. These capacitors consist of elastomer film sandwiched between two compliant electrodes. When voltage is applied the electrode squeeze the elastomer film. The film contracts in the thickness direction and expands in the plane direction. When short-circuited elastomer film returns back to its original position.

vhb ( very high bond) polymer film 3M 4905

first electroactive polymer actuator test / vhb polymer, graphite powder, copper tape, acrylic frame

first electroactive polymer actuator test / after couple of weeks

application of electroactive polymer actuators and sensors:
haptic feedback / pumps / valves / robotics / prosthetics / power generation / active vibration control of structures / optical positioners such for auto-focus, zoom, image stabilization / sensing of force and pressure / active braille displays / speakers / deformable surfaces for optics and aerospace / energy harvesting