Palm Interface Has You Suggest where Self Driving Car Should Go

These days, our automobiles sport glittering consoles adorned with dials and digits to keep us up-to-date with our car’s vitals. In the future, though, perhaps we just wont need such vast amounts of information at our fingertips if our cars are driving themselves around. No information? How will we tell the car what to do? On that end, [Felix] has us covered with Stewart, a tactile gesture-input interface for the modern, self driving car.

Stewart is a 6-DOF “Stewart Interface” capable of both gesture input and haptic-output. Gesture input enables the car’s passenger to deliver driving suggestions to the car. The gentle twist of a wrist can signal an upcoming turn at the next intersection; pulling back on Stewart’s head “joystick style” signals a “whoa–slow down, there, bub!” Haptic output via 6 servos pushes around Stewart’s head in the car’s intended direction.  If the passenger agrees with the car, she can let Stewart gesture itself in the desired direction; if she disagrees; she can veto the car’s choices by moving her hand directly against Stewart’s current output gesture. Overall, the interface unites the intentions of the car and the intentions of the passenger with a haptic device that makes the connection feel seamless!

We know we’re not supposed to comment on the “how” with art projects–but we’re engineers–and this one makes us giddy with delight. We’re imagining those rc car shock absorbers dramatically dampening the jittery servos and giving the user a nice resistive feel. Interconnects are laser cut acrylic, and the shell is a smoothly contoured 3d print. We’ve seen Stewart Interfaces before, but nothing with the look-and-feel of a sleek design feature on its way to being dropped into the cockpit of our future self-driving cars.

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Nothing’s as Vain as a Phone Taking a Selfie of Itself… with Itself

The selfie: pop culture’s most frivolous form of self-expression is also probably one of the most human acts you could find yourself doing in a day. Everyone is guilty of snapping a quick pic from time to time with the expectation that it will leave an impression on those who see it. All of the implications surrounding why we do this support our deep-seated need to sculpt an identity for ourselves using others as the hammer and chisel. So, consider how upside-down the world would feel if you caught a robot posing for a shot in the mirror? What about one whose sole function was to take selfies and post them? If this breaks your mind a little, that was the intention. This #selfie robot by artists [Radamés Ajna] and [Thiago Hersan] is the first development in a larger body of work called “memememe”, which is meant to comment on our culture’s obsession with the trending, selfing nature of social media. This specific project explores the relationship between conversation and identity in a situation where there is no second party.

selfieBOT2Hardware-wise, the #selfie bot is a Stewart platform made from six servo motors and a few pieces of carefully measured pushrod connected with swivel-ball-links. An android phone is mounted on the end effector which acts functionally as the robot’s face and eyes. To make it self-aware in a sense, [Ajna] and [Hersan] created their own recognition software with Open CV using a collection of sample images of various phones as reference points. As soon as the robot recognizes itself in the mirror as indicated by specific words flashing on its screen, it takes a picture, immediately uploading it to its own tumblr account. [Ajna] and [Hersan] have a nice description of their process on the project’s Instructable’s page which you can check out to see how they used Haar Cascades to create their custom object recognition. Additionally, if you’d fancy building your own robot to covertly place in your living room to snap pictures of other phones, you could check out their code on github.

Watch it selfie :

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Stewart Platform Ball Bearing Balancer

PID balancing a ball on a plate

For their Mechanical Engineering senior design project at San Jose State University, [Tyler Kroymann] and [Robert Dee] designed and built a racing motion simulator. Which is slightly out of the budget of most hackers, so before they went full-scale, a more affordable Arduino powered Stewart platform proof of concept was built. Stewart platforms typically use six electric or hydraulic linear actuators to provide motion in six degrees of freedom (6 DOF), surge (X), sway (Y), heave (Z), pitch, roll, and yaw. With a simple software translation matrix, to account for the angular displacement of the servo arm, you can transform the needed linear motions into PWM signals for standard hobby servos.

The 6 DOF platform, with the addition of a resistive touch screen, also doubled as a side project for their mechatronic control systems class. However, in this configuration the platform was constrained to just pitch and roll. The Arduino reads the resistive touch screen and registers the ball bearing’s location. Then a PID compares this to the target location generating an error vector. The error vector is used to find an inverse kinematic solution which causes the actuators to move the ball towards the target location. This whole process is repeated 50 times a second. The target location can be a pre-programmed or controlled using the analog stick on a Wii nunchuck.

Watch the ball bearing seek the target location after the break.

Thanks to [Toby] for sending in this tip.

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Stewart Platform reinvents the wheel so you don’t have to


[Dan Royer] has noticed that most university projects involving a Stewart platform spend more time building a platform than on the project itself. He hopes to build a standard platform universities can use as the basis for other projects.

Stewart platforms are six degree of freedom platforms often seen hefting flight simulators or telescopes. The layout of the actuators allows movements in X,Y,and Z as well as pitch, roll and yaw. While large platforms often use hydraulic systems to accelerate heavy loads quickly. [Dan] is looking at a smaller scale system. His platform is built of laser cut wood and uses six steppers to control motion.

One of the harder parts in designing a platform such as this is creating a mechanical system that is strong, precise, and smooth. With so many linkages, it’s easy to see how binding joints could bring the entire thing to a grinding halt. [Dan] is currently using RC helicopter ball joints, but he’s on the lookout for something even smoother.

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