It Turns Out, Robots Need Tough Love Too

Showing robots adversarial behavior may be the key to improving their performance, according to a study conducted by the University of Southern California. While a generative adversarial network (GAN), where two neural networks compete in a game, has been demonstrated, this is the first time adversarial human users have been used in a learning effort.

The report was presented at the International Conference on Intelligent Robots and Systems, describing the experiment in which reinforcement learning was used to train robotic systems to create a general purpose system. For most robots, a huge amount of training data is necessary in order to manipulate objects in a human-like way.

A line of research that has been successful in overcoming this problem is having a “human in the loop”, in which a human provides feedback to the system in regards to its abilities. Most algorithms have assumed a cooperating human assistant, but by acting against the system the robot may be more inclined to develop robustness towards real world complexities.

The experiment that was conducted involved a robot attempting to grasp an object in a computer simulation. The human observer observes the simulated grasp and attempts to snatch the object away from the robot if the grasp is successful. This helps the robot discern weak and firm grasps, a crazy idea from the researchers that managed to work. The system trained with the adversary rejected unstable grasps, quickly learning robust grasps for different objects.

Experiments like these can test the assumptions made in the learning task for robotic applications, leading to better stress-tested systems more inclined to work in real-world situations. Take a look at the interview in the video below the break.

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2D-Platform Seeks Balance With A Touch Screen

It’s the [Bruce Land]-iest season of all, when the Cornell professor submits the projects his microcontroller class students have been working on all semester. Imagination does not seem to be in short supply with these students, and we always look forward to these tips this time of year.

[Greg] and [Sam]’s touch-screen two-dimensional ball balancer is a good example of what [Land]’s students turn out. The resistive touch screen is supported by a 3D-printed gimballed platform and tilted in two axes by hobby servos. [Greg] and [Sam] chose to read the voltage outputs from the touch screen directly using the ADC on a PIC32, toggling between the two axes at 2 kHz. Two PID control loops were implemented to keep the ball as centered as possible on the platform, and the video below shows that there’s still some loop tuning to do. But given the positional inaccuracies of hobby servos and the compliance in the gimbal, we’re impressed that they were able to keep the system under control at all.

Of course we’ve seen ball-balancers before, but most of them have closed the loop using either cameras or microphones. Seeing direct sensing on the platform like this is a nice change of pace. Continue reading “2D-Platform Seeks Balance With A Touch Screen”

OpenDog: Adding Force Sensitive Feet

[James Bruton] OpenDog remains one of the most impressive home-built robotics projects we’ve seen here on Hackaday, and it’s a gift that just keeps on giving. This time he’s working on adding force sensing capabilities to OpenDog’s legs to allow for more dynamic movement control.

The actuators in the legs are three-phase outrunner motors that drive ball-screws via a belt. This configuration is non-backdrivable, meaning the legs cannot be moved when an external force is, which could lead to mechanical failures. He as tested other backdrivable leg configurations with other robots, but did not want to rebuild OpenDog completely. The solution [James] went with is a redesigned foot with an inbuilt switch, to confirm that the foot is touching the ground, and a load cell attached in the middle of the bottom leg segment. The load cell is bolted rigidly onto the leg segment, which allows it to sense when the leg is carrying load, without damaging the load cell itself.

Unfortunately all the serial ports on OpenDog’s main Teensy 3.6 controller are already used, so he converted the signal from the load cell to PWM, to allow it to be read by a normal GPIO pin. This works well in isolation, but when [James] switches on the motors, the PWM signal from the load sensor gets flooded by interference, making it unreadable. To solve this problem, he wants to implement a CAN bus, which will allow for more inputs and outputs and hopefully solve the interference problem. However, [James] has no experience with the CAN protocol, so learning to use it is going to be a project on its own.

OpenDog is turning into a very lengthy, time-consuming project, [James] says that the lessons learned from it have been invaluable for a number of other projects. This is something to keep in mind with everything we tackle. Choose projects were the experience gained and/or relationships developed are worth it on their own, even when the project fails in a conventional sense. This way you can never really lose.

A Soft Robotic Insect That Survives The Fly Swatter

Swarms of robotic insects incapable of being swatted away may no longer be the product of science fiction and Black Mirror episodes. A team from EPFL’s School of Engineering has developed an insect propelled at 3 cm/s, dubbed the DEAnsect.

What makes this robot unique is its exceptional robustness. Two versions of the robot were initially developed, one tethered with ultra-thin wires capable of being squashed with a shoe without impacting its functions and the second fully wireless and autonomous. The robot weighs less than 1 gram and is equipped with a microcontroller and photodiodes to recognize black and white patterns.

The insect is named for its dielectric elastomer actuators (DEAs), an artificial muscle that propels it with vibrations and enables it to move lightly and quickly.

The DEAs are made of an elastomer membrane wedged between soft electrodes that are attracted to each other when a voltage is applied, compressing the membrane. The membrane returns to its original shape when the voltage is turned off. Movement is generated by switching the voltage on and off over 400 times per second. The team reduced the thickness of the membranes and developed soft, highly conductive electrodes only several molecules thick using nanofabrication techniques. They plan on fitting even more sensors and emitters to allow the insects to communicate directly with one another for greater swarm-like activity.

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Jeremy Cook Is Living His Strandbeest Dream

The first thing Jeremy Cook thought when he saw a video of Theo Jansen’s Strandbeest walking across the beach was how incredible the machine looked. His second thought was that there was no way he’d ever be able to build something like that himself. It’s a feeling that most of us have had at one time or another, especially when starting down a path we’ve never been on before.

But those doubts didn’t keep him from researching how the Strandbeest worked, or stop him from taking the first tentative steps towards building his own version. It certainly didn’t happen overnight. It didn’t happen over a month or even a year, either.

ClearCrawler at the 2019 Hackaday Superconference

For those keeping score, his talk at the 2019 Hackaday Superconference, “Strandbeests: From Impossible Build to Dominating My Garage” is the culmination of over six years of experimentation and iteration.

His first builds could barely move, and when they did, it wasn’t for long. But the latest version, which he demonstrated live in front of a packed audience at the LA College of Music, trotted across the stage with an almost otherworldly smoothness. To say that he’s gotten good at building these machines would be something of an understatement.

Jeremy’s talk is primarily focused on his Strandbeest creations, but it’s also a fascinating look at how a person can gradually move from inspiration to mastery through incremental improvements. He could have stopped after the first, second, or even third failure. But instead he persisted to the point he’s an expert at something he once believed was out of his reach.

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FET Based Motor Driver Is Better Than L298N

If you want to build a small robot with a motor, you are likely to reach for an L298N to interface your microcontroller to the motor, probably in an H-bridge configuration. [Dronebot] has used L298N chips like this many times. In the video below, he uses a TB6612FNG instead, taking advantage of the device’s use of MOSFETs. The TB6612 may be a little more expensive, but it’s clearly worth it.

You can get breakout boards for the tiny chips. [DroneBot] looks at several ready-to-go breakout boards. They are not drop-in compatible, though. For example, the L298N can operate motors from 4.5 to 46V while the TB6612 can go from 2.5 to 13.5V on the motor voltage. The L298N also handles more current. However, because of its relatively low efficiency, it needs a heat sink. The TB6612 boasts up to 95% efficiency and also has a low current standby mode. Of course, the TB6612 drops much less voltage which is great if you are using low voltage motor.

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Robot Insect Survives Swatting

There is an old saying, that ‘the hand is quicker than the eye;, but somewhat slower than the fly.” However, with a little practice you can swat a fly, although it sometimes doesn’t seem to faze the fly. École polytechnique fédérale de Lausanne (EPFL) has announced they have used nanotech to build a 1 gram possibly untethered, autonomous robotic insect that has enough processing power and sensors to recognize black and white patterns. Artificial muscles provide propulsion. But there’s the kicker: it can survive a strike with a fly swatter.

In the video you see below, the robots can move at 3 centimeters per second and there are two different versions. The first is a tethered system using ultra-thin wires. This is the version that can be folded, smacked, or even squashed by a shoe and continue moving.

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