Archive for June, 2019

How To Choose Your PCB Design Software to Design Open-Source Hardware

June 14th, 2019 No comments
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This Total Solar Eclipse Film Took Two Years to Finish

June 12th, 2019 No comments
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Purdue Now Offers Graduate Certificate For Current And Prospective STEM Faculty

June 5th, 2019 No comments

Purdue’s School of Engineering Education (ENE), the first of its kind, is offering an online 10-credit hour graduate certificate in Teaching and Learning in Engineering. ENE has teamed with Purdue Online to offer this unique certificate program for current or prospective faculty members in STEM fields. Courses include Engineering Education Methods and Content, Assessment and Pedagogy. For more information and to apply, visit Purdue’s Teaching and Learning in Engineering page.

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Ford Self-Driving Vans Will Use Legged Robots to Make Deliveries

June 5th, 2019 No comments

from IEEE Spectrum 22 May 2019

Ford is adding legs to its robocars—sort of.

The automaker is announcing today that its fleet of autonomous delivery vans will carry more than just packages: Riding along with the boxes in the back there will be a two-legged robot.

Digit, Agility Robotics’ humanoid unveiled earlier this year on the cover of IEEE Spectrum, is designed to move in a more dynamic fashion than regular robots do, and it’s able to walk over uneven terrain, climb stairs, and carry 20-kilogram packages.

Ford says in a post on Medium that Digit will bring boxes from the curb all the way to your doorstep, covering those last few meters that self-driving cars are unable to. The company plans to launch a self-driving vehicle service in 2021.

Digit performs flawlessly in the video, although it wasn’t operating fully autonomously. It was being teleoperated at a high level via commands like “walk to this location,” “climb the stairs,” and “put down the box.” We’re told that Digit didn’t fall over even once during filming, but certainly a bigger challenge for the robot will be to perform this well across the wide variety of homes that it may eventually have to handle, with obstacles like inclined surfaces, different types of stairs, overgrown yards, gates, and wayward pets and/or children. Having a vehicle serve as a base station provides a variety of advantages for Digit. It can carry a smaller battery because it will frequently return to the vehicle to recharge. And while it has cameras and a lidar, Digit will have help from the vehicle to do mapping and path planning

Having a vehicle serve as a base station provides a variety of advantages for Digit. For example, Digit can get away with a much smaller battery than most large humanoids, because it only really needs to operate for a few minutes at a time before returning to the vehicle to recharge as it drives to the next delivery stop. And while Digit carries several stereo cameras and a lidar, it will have help from its companion robovan to do much of the mapping and path planning required to carry out a delivery. That’s an advantage, Ford says, because its autonomous vehicles are equipped with much more powerful sensors and computers than Digit could carry alone.

From the Medium post:

Digit itself will have just enough sensory power to travel through basic situations. If it comes across an unexpected obstacle, it can send an image back to the vehicle and have the car figure out a solution. The car could even send that information into the cloud and ask for other systems to help Digit navigate its environment, providing multiple levels of added assistance while keeping the robot light and nimble.

Digit robot coming out of self-driving van
Image: Ford

This is a very interesting concept, and to learn more about it (and about how Digit will handle all the rest of this operation), we spoke with Agility Robotics CEO Damion Shelton.

IEEE Spectrum: Offloading the sensing and computing required for autonomous navigation is a very interesting idea—can you break down what will be done on the robot and what will be done on the vehicle? 

Damion Shelton: The exact split is still to be determined, but the basic idea is to run things that require real-time (or close to it) processing on the robot, and push other tasks off-board. Examples of the former are things like footstep placement, low-level postural control, execution of previously trained RL behaviors, and path-planning out to 3 to 5 steps. Tasks that could be pushed to the vehicle include storage and retrieval of maps, training of RL behaviors, and initialization of the robot’s global pose during deployment. The initialization of global pose is actually one of the most important things the vehicle can be used for, in our view. Absent that, Digit would need to build a local world model from ground zero every time it gets out of the vehicle.

Having bipedal robots that are mechanically capable of traversing semi-structured terrain is often very far from having bipedal robots that are actually able to reliably operate in semi-structured terrain without human supervision. How will you develop the confidence to deploy Digit in real-world use, and what are the biggest challenges you’ll need to solve?

We don’t anticipate operating without human supervision for quite a while. The form that this takes will relax over time; initially, we would expect a human to be present in the immediate vicinity of the robot during operation. After we’re confident that the performance in a particular geofenced area is reliable, direct monitoring could be replaced with “call center” style central monitoring, but that’s a minimum of several years out. From the perspective of data gathering and continued refinement of both hardware and software, the fact that monitoring is required in the immediate future isn’t really a detriment. Particularly in collaborative applications—say, where the robot is a labor assistant to a delivery driver—the additional cost to have a human partially in the loop is close to zero (since the driver is already doing the work now).

Digit delivering package from Ford autonomous vehicle
Photo: Ford and Agility Robotics

Digit will likely have to interact with a variety of non-deterministic, dynamic obstacles, like other people or pets. How much of a concern is having reliable autonomy when there’s potential for all kinds of unpredictable edge cases?

From a test deployment standpoint (tens to hundreds of robots in scale) our plan is to avoid edge cases that we’re not able to handle and allow just enough uncertainty into the mix to keep our R&D moving forward. For the first 12 to 18 months of testing—starting in early 2020—we anticipate pre-mapping and qualifying all of the environments we operate in. This is what the majority of autonomous vehicle companies have done: Geofence an area you understand, and get comfortable there before expanding. It’s certainly true that we won’t be able to deal with a majority of the “hard problems” in the world early on, but we don’t see that as a barrier to deployment. We don’t need to address the most difficult cases, since even the easiest 1/10th of a percent of market is enormous relative to any plausible sustained growth rate.

But that’s not to minimize the difficulty of the edge cases. You’re exactly correct that reliability in the real world is challenging—we hope that by getting Digits out in the world as soon as possible, we start to collect data on the hard problems even if we don’t (yet) have a deployable solution.

Will Digit be able to interact with humans directly? What would those interactions look like?

We’re not super focused on human-robot interaction problems, other than as they relate to mobility. In a perfect world, Digit blends into the background and interactions are primarily non-verbal. You know that other pedestrians aren’t going to run into you on a sidewalk by having a mental model of posture, gait dynamics, and so on. We think a lot about those kinds of dynamic cues, but don’t have plans to turn Digit into a witty conversationalist. That being said, the production version of Digit is going to have a speaker on it, and a light display, both of which can be used to provide minimalist feedback to the outside world.

Is this the application you had in mind when you designed Digit? What other kinds of things would you like to see Digit doing?

Yes, at least in the sense that we believed from the beginning that the best early market for Digit would be in logistics. It’s a market that requires the mobility of legs (at least in the areas we’re focusing on) while not requiring super advanced AI (in “easy” environments), FDA certification (e.g. in-home assistive robotics for the elderly), or harsh environment operations (e.g. firefighting). Basically, if you can move through the world and carry a box, you’ve addressed the absolute minimalist use case for logistics.

Delivery services are a large and rapidly growing industry, which also gives us the ability to focus on a profitable use-case from day one. Many of the “dull dirty dangerous’ jobs that robots are usually targeted at are both quite challenging and and relatively low volume. Legs have been talked about for years as a tool for disaster recovery, search and rescue, and so on, but these are enormously challenging environments to move through and the business case is hard to rationalize out of the gate. Conversely, if we have a fleet of Digits that learn to move through the world with the large training set of last-mile environments, and then simultaneously have the cost pressure and economy of scale of a commercial deployment, the odds of us then being able to offer a competitive product in more specialized markets goes up dramatically.

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How Servo Motors Work?

June 4th, 2019 No comments

From: Jameco Electronics

Servo Motor Controllers

This little motor is high in efficiency and power

Servo motors have been around for a long time and are utilized in many applications. They are small in size but pack a big punch and are very energy-efficient. These features allow them to be used to operate remote-controlled or radio-controlled toy cars, robots and airplanes. Servo motors are also used in industrial applications, robotics, in-line manufacturing, pharmaceutics and food services. But how do the little guys work?

The servo circuitry is built right inside the motor unit and has a positionable shaft, which usually is fitted with a gear (as shown below). The motor is controlled with an electric signal which determines the amount of movement of the shaft.

What’s inside the servo?

To fully understand how the servo works, you need to take a look under the hood. Inside there is a pretty simple set-up: a small DC motor, potentiometer, and a control circuit. The motor is attached by gears to the control wheel. As the motor rotates, the potentiometer’s resistance changes, so the control circuit can precisely regulate how much movement there is and in which direction.

When the shaft of the motor is at the desired position, power supplied to the motor is stopped. If not, the motor is turned in the appropriate direction. The desired position is sent via electrical pulses through the signal wire. The motor’s speed is proportional to the difference between its actual position and desired position. So if the motor is near the desired position, it will turn slowly, otherwise it will turn fast. This is called proportional control. This means the motor will only run as hard as necessary to accomplish the task at hand, a very efficient little guy.

How is the servo controlled?

Servos are controlled by sending an electrical pulse of variable width, or pulse width modulation (PWM), through the control wire. There is a minimum pulse, a maximum pulse, and a repetition rate. A servo motor can usually only turn 90° in either direction for a total of 180° movement. The motor’s neutral position is defined as the position where the servo has the same amount of potential rotation in the both the clockwise or counter-clockwise direction. The PWM sent to the motor determines position of the shaft, and based on the duration of the pulse sent via the control wire; the rotor will turn to the desired position. The servo motor expects to see a pulse every 20 milliseconds (ms) and the length of the pulse will determine how far the motor turns. For example, a 1.5ms pulse will make the motor turn to the 90° position. Shorter than 1.5ms moves it in the counter clockwise direction toward the 0° position, and any longer than 1.5ms will turn the servo in a clockwise direction toward the 180° position.

When these servos are commanded to move, they will move to the position and hold that position. If an external force pushes against the servo while the servo is holding a position, the servo will resist from moving out of that position. The maximum amount of force the servo can exert is called the torque rating of the servo. Servos will not hold their position forever though; the position pulse must be repeated to instruct the servo to stay in position.

Types of Servo Motors

There are two types of servo motors – AC and DC. AC servo can handle higher current surges and tend to be used in industrial machinery. DC servos are not designed for high current surges and are usually better suited for smaller applications. Generally speaking, DC motors are less expensive than their AC counterparts. These are also servo motors that have been built specifically for continuous rotation, making it an easy way to get your robot moving. They feature two ball bearings on the output shaft for reduced friction and easy access to the rest-point adjustment potentiometer.

Servo Motor Applications

Servos are used in radio-controlled airplanes to position control surfaces like elevators, rudders, walking a robot, or operating grippers. Servo motors are small, have built-in control circuitry and have good power for their size.

In food services and pharmaceuticals, the tools are designed to be used in harsher environments, where the potential for corrosion is high due to being washed at high pressures and temperatures repeatedly to maintain strict hygiene standards. Servos are also used in in-line manufacturing, where high repetition yet precise work is necessary.

Of course, you don’t have to know how a servo works to use one, but as with most electronics, the more you understand, the more doors open for expanded projects and projects’ capabilities. Whether you’re a hobbyist building robots, an engineer designing industrial systems, or just constantly curious, where will servo motors take you?

Servo Motor Buyer Guide

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Earth and the moon

June 4th, 2019 No comments

From Daily Overview Mar 5, 2018

Earth and the moon, separated by 249,000 miles (400,000 km). Sometimes it takes an image like this to really keep things in perspective. This photograph was captured by NASA’s OSIRIS-REx spacecraft on September 22, 2017 when it was 804,000 miles (~ 1.3 million km) from Earth and 735,000 miles (~ 1.19 million kilometers) from the Moon. The spacecraft is currently en route to the asteroid Bennu where it will land, collect samples, and then return back to Earth on September 24, 2023.

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Radio Electronics Magazine Archive

June 4th, 2019 No comments
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How To: Surface Mount Soldering

June 4th, 2019 No comments

Here is a link to an article on surface mount soldering. With it getting harder and harder to find through hole parts, it is a skill all electronics hobbyist and professionals need to master.

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