Manufacturing, Control, and Performance Evaluation of a Gecko-Inspired Soft Robot

This technique uses a soft robotics toolkit to manufacture our Gecko inspired soft robot, which can be manipulated by an universal pneumatic control box. Using a soft climbing robot enables a wide variety of applications that impose high demands on the machine. For example, for cleaning of solar mirrors or skyscraper facades.

Basically any other soft robot can be manufactured using this method in any pneumatic system can be operated with a controller box. The manufacturing of the actuators is mostly done by hand and requires practice. Do not expect it to work perfectly on the first try.

To prepare the elastomer, add five grams of elastomer Part B compound, and 45 grams of Part A compound per actuator to a cup on a balance. And stir the cup contents until no white or red areas are visible at the edge of the cup. Then place the cup in a vacuum chamber for 15 minutes to remove any air that became trapped in the elastomer during the stirring process.

And load the die cast elastomer into a 50 milliliter syringe. To manufacturer of the base part first clamp acrylic glass plate with two corresponding holes onto the mold and insert the syringe into the lower hole. Depress the plunger to load the elastomer into a leg or torso mold.

When the compound emerges from the upper hole, loosen the screw clamps and pull the acrylic glass plate sideways off of the mold. Use a sharp tool to puncture any rising air bubbles. Then add extra elastomer.

Puncture the rising bubbles again and place the mold in was 65 degrees Celsius oven. After 30 minutes take the mold from the oven and use a cutter knife to remove an extruded elastomer. Insert a lever arm between the mold pieces to open it without damaging the casting surfaces and remove the almost actuator piece from the mold.

If the casting was successful, use the cutter knife to remove any protruding bands. To manufacturer of the suction cups and the bottom part of the torso follow the same procedure but without the use of additional acrylic glass plates. To manufacturer of the lower part of the leg push a silicone tube through the holes in the bottom part of the mold and fill the mold with elastomer.

Then use a small spatula to distribute the elastomer to the corners of the mold and cure the mold in the oven for 15 to 20 minutes. When the bottom of the casting is cooled, fill the mold of the bottom part with fresh elastomer, to one to 1.5 millimeters above the already hardened elastomer and insert a butterfly cannula into the base casting. After marking the puncture site for later identification, place the upper base into the bottom mold and slightly press the sides into the elastomer bath.

After 10 to 15 minutes in the oven, remove the actuator from the mold and use the puncture site to connect the device to a pressure source to perform a final leakage test. To manufacture the torso fill the bottom part with elastomer and place the base part into the bottom part. To prepare the limb joining surface cover the joining surface with elastomer and use pin needles to fix the parts to be joined onto a wooden board.

After curing, join the suction cups with the legs attached needles in the torso to ensure that all parts are in the same plane, then you're the assembly for an additional 10 to 15 minutes. Use a one millimeter allen key to widen the insertion point and place the end of a no more than three millimeter diameter silicone tube over the insertion hole. Use the key to press the tube into the hole and seal the inlet with a small amount of elastomer.

Then cure the assembly in the oven for another 10 minutes. To set up the entire system connects supply tubes to the inlets of all actuators. Connect the supply tubes embedded in the legs with the suction cups, and use pin needles to attach the markers to the robot.

Connect the robot to the control box and connect a pressure source with a maximum pressure of 1.2 bars and a vacuum source to the control box. To perform a climbing experiment, place the robot at the starting point of the walking plane and start the recording. Press function one to activate the pressure controller and let the robot walk and climb for at least six cycles.

Press record to stop the recording and make sure that the robot will not fall when the pressure controller is stopped. Then press function one to stop the pressure controller. It is necessary to adapt the calibration procedure to the real operating conditions as closely as possible.

When changing the inclination angle of the walking plane, the operating conditions change as well. Therefore, the angle pressure curve must be recalibrate for each inclination. After the recalibration in this analysis, the robot was not only faster it was also able to climb steeper inclines while consuming less energy.

In these images, the motion of the robot for an inclination of 48 degrees is shown. As illustrated the climbing performance of the robot was significantly improved after the recalibration as the shift in position within the same time interval is almost twice as large. As we have observed with the suction cups, different complex shapes can be produced with this manufacturing method.

Even those with undercuts. When joining the individual parts, it is very important that ally in the same plane, otherwise the climbing ability of the robot will be drastically reduced. The robot is an interesting platform for researching new motion strategies.

For example, running a curve can be performed by this robot in very different ways.