A Novel Origami-Inspired Delta Mechanism With Flat Parallelogram Joints

Abstract

In robotics, origami-based design methodology can be used to create small scale parallel mechanisms with easier assembly processes. Delta mechanisms are one of the famous parallel mechanism used mostly in pick and place operations due to their capability to reach high speeds and accelerations. In this work, we present a novel Delta mechanism fabricated with fully 2D layer by layer methods. In our design we have eliminated manual 3D processes in order to provide parallel movement of the links. We have designed a new flat parallelogram providing pure translations in X-Y-Z directions respecting to the conventional kinematic models for Delta mechanism. The assembly process is reduced to an only cut – laminate – repeat steps which are very basic operations in 2D. The kinematic performance of the mechanism has been analyzed using a 6 DoF position sensor placed on the end-effector. The mechanism has a 20x20x20 mm3 cubic stable workspace with a 17.5 mm radius circular footprint when it is completely flat. The tests were done for circular trajectories having 10 mm radius circles with different heights and circles with different radiuses in a specific height. Despite having no feedback control from the end effector, the mechanism was able to follow the trajectory with 1.5 mm RMS precision. We have also changed the materials of the flexible layers in passive links and presented the trajectory results of the end-effector showing how it effects the kinematic performance of the mechanism.

Feedback Control of a Foldable Delta Mechanism with Integrated Inkjet-Printed Angle Sensors

“…A sensorless Delta mechanism was designed and fabricated as a foldable robot, with a layer-by-layer fabrication method in our previous work [20]. In this study, we govern the same fabrication process but integrate inkjet-printed sensors into the active joints of the robot.…”

“…Adhesive layer contact with the sensor print area is avoided, due to the damage and failures observed in the adhesive covered specimens. The remaining parts of the Delta mechanism were designed and fabricated as was presented in our previous study in detail [20], Figure 1. Note that in this study the castellated joint designs in [20] are used only in the passive joints, and flat profiles are used in the sensor integrated joints, to maintain a uniform boundary condition for the sensors (Figure 1).…”

“…The remaining parts of the Delta mechanism were designed and fabricated as was presented in our previous study in detail [20], Figure 1. Note that in this study the castellated joint designs in [20] are used only in the passive joints, and flat profiles are used in the sensor integrated joints, to maintain a uniform boundary condition for the sensors (Figure 1). In case of an actuator integration other than the DC motor and the rigid setup which defines a stable joint axis for the active joints (e.g.…”

“…In this study, we achieved to fabricate a foldable Delta robot with angle feedback in its active joints, without adding any extra assembly steps to the existing fabrication process of the sensorless Delta robot [20]. We have printed resistive sensors on the already existing structural flexible PET layer of the robot using an office type inkjet printer and silver nanoparticle (Ag NP) ink.…”

“…After the sensor integration, platform is cut through the lighter dashed lines given in (3.(a)). The straightforward fabrication methodology is followed [20] to fabricate the top platform, assembly the top and the bottom, and perform the final cut (Darker dashed line in (3. (a))) resulting with the mechanism shown in (5).…”