The most common suspension systems on automobiles rely on simple metal springs. Leaf spring and coil spring designs both have their pros and cons, but fundamentally it’s all about flexing metal doing the work. Air suspension works altogether differently, employing gas as a spring, as demonstrated by this simple Lego build from [JBRIX].
The suspension system is employed on a Lego Technic car, with a relatively unsophisticated design. The car has no real form of propusion, and serves solely to demonstrate the air suspension design. They may look like dampers, but the system is actually using Lego pneumatic pistons as springs for each wheel. The pistons are connected to the upper control arm of a double wishbone suspension setup. Each piston is pneumatically connected to a main reservoir. With the reservoir, and thus the pistons, pressurized, the suspension system can support the weight of the car. If a bump perturbs a wheel, the piston compresses the air in the system, which then returns the piston to its original position, thus serving as a spring. If the reservoir is vented, the suspension collapses. Air springs on real, full-sized automobiles work in basically the same way. However, they usually have a separate reservoir per corner, keeping each wheel’s suspension independent.
Overall, if you’re working on some kind of Lego rambler, you might find this suspension concept useful. Alternatively, you might simply find it good as a learning aid. If you want to learn more about oddball suspension systems, we can help there too. Video after the break.
Riding a bike is a pretty simple affair, but like with many things, technology marches on and adds complications. Where once all you had to worry about was pumping the cranks and shifting the gears, now a lot of bikes have front suspensions that need to be adjusted for different riding conditions. Great for efficiency and ride comfort, but a little tough to accomplish while you’re underway.
Luckily, there’s a solution to that, in the form of this active suspension system by [Jallson S]. The active bit is a servo, which is attached to the adjustment valve on the top of the front fork of the bike. The servo moves the valve between fully locked, for smooth surfaces, and wide open, for rough terrain. There’s also a stop in between, which partially softens the suspension for moderate terrain. The 9-gram hobby servo rotates the valve with the help of a 3D printed gear train.
But that’s not all. Rather than just letting the rider control the ride stiffness from a handlebar-mounted switch, [Jallson S] added a little intelligence into the mix. Ride data from the accelerometer on an Arduino Nano 33 BLE Sense was captured on a smartphone via Arduino Science Journal. The data was processed through Edge Impulse Studio to create models for five different ride surfaces and rider styles. This allows the stiffness to be optimized for current ride conditions — check it out in action in the video below.
[Jallson S] is quick to point out that this is a prototype, and that niceties like weatherproofing still have to be addressed. But it seems like a solid start — now let’s see it teamed up with an Arduino shifter.
While you might have bought the best pair of skis in the 90s or 00s, as parts on boots and bindings start to fail and safety standards for ski equipment improve, even the highest-quality skis more than 15 or 20 years old will eventually become unsafe or otherwise obsolete. There are plenty of things that can be done with a pair of old skis, but if you already have a shot ski and an Adirondack chair made of old skis, you can put another pair to use building one of the fastest sleds we’ve ever seen.
[Josh Charles], the creator of this project, took inspiration from his father, who screwed an old pair of skis to the bottom of an traditional runner sled when he was a kid. This dramatically increased the speed of the sled, but eliminated its ability to steer. For this build [Josh] built a completely custom frame rather than re-use an existing sled, which allowed him to not only build a more effective steering mechanism for the skis, but also to use bicycle suspension components to give this sled better control at high speeds.
In automotive engineering, almost every design choice is a trade-off, like performance versus fuel economy, straight-line speed versus cornering, or strength versus weight. Inspired by controversial technology for the 2020 Formula 1 season, [Wesley Kagan] is fitting his DIY racing car with actuators to change the suspension geometry while driving.
The controversial technology in question is Mercedes’ DAS (Dual Axis Steering). By pushing the steering wheel in and out, the driver and change the wheel alignment to toe-out (wheels pointing outwards) for better cornering stability, or neutral for the straight sections.
Like many racing cars, [Wesley] used A-arm suspension on his racing car. By replacing the top arms with telescoping tubes with mounted actuators, the geometry can be actively adjusted. For this proof of concept, he used linear actuators but plans to move to a hydraulic system for improved speed and force. The length of the A-arms is sensed with ultrasonic sensors, while a potentiometer senses the suspension position.
Tuning the software for optimum performance will probably require some track testing which we hope to see in the future. This is not the first time [Wesley] has taken inspiration from a multimillion-dollar project and implemented it in his garage. Just check out how he converted a Miata and a Harbor Freight engine to a Free Valve system.
Active suspensions are almost a holy grail for cars, adding so much performance gain that certain types have even been banned from Formula 1 racing. That doesn’t stop them from being used on a wide variety of luxury and performance cars, though, as they can easily be tuned on the fly for comfort or improved handling. They also can be fitted to remote controlled cars as [Indeterminate Design] shows with this electronic servo-operated active suspension system for his RC truck.
Each of the four servos used in this build is linked to the mounting point of the existing coilover suspension on the truck. This allows the servo to change the angle that the suspension is positioned while the truck is moving. As a result, the truck has a dramatic performance enhancement including a tighter turning radius, more stability, and the capability of doing donuts. The control system runs on an Arduino with an ESP32 to enable live streaming of data, and also includes an MPU6050 to monitor the position of the truck’s frame while it is in motion.
There’s a lot going on in this build especially with regard to the control system that handles all of the servos. Right now it’s only programmed to try to keep the truck’s body relatively level, but [Indeterminate Design] plans to program several additional control modes in the future. There’s a lot of considerations to make with a system like this, and even more if you want to accommodate for Rocket League-like jumps. Continue reading “Remote Controlled Car Gets Active Suspension”→
In addition to driving home the need for Steadicam or Optical Image Stabilization, this eighty-year-old video illustrates some elegant solutions the automotive industry developed in their suspension systems. Specifically, this Chevrolet video from 1938 is aimed at an audience that values science and therefore the reel boils down the problem at hand using models that will remind you of physics class.
The problem is uneven ground — the “waves in the Earth’s surface” — be it the terrain in an open field, a dirt road, or even a paved parkway. Any vehicle traveling those surfaces will face the challenge of not only cushioning for rough terrain, but accounting for the way a suspension system itself reacts to avoid oscillation and other negative effects. In the video this is boiled down to a 2-dimensional waveform drawn by a model which begins with a single tire and evolves to include a four wheeled vehicle with different suspension systems in the front and the rear.
Perhaps the most illuminating part of the video is the explanation of how the car’s front suspension actually works. The wheels need to be able to steer the vehicle, while the suspension must also allow the tire to remain perpendicular to the roadway. This is shown in the image at the top of this article. Each wheel has a swing arm that allows for steering and for vertical movement of the wheel. A coil spring is used in place of the leaf springs shown in the initial model.
You probably know what’s coming next. The springs are capable of storing and releasing energy, and left to their own devices, they’ll dissipate the energy of a bump by oscillating. This is exactly what we don’t want. The solution is to add shock absorbers which limit how the springs perform. The waveforms drawn by the model encountering bumps are now tightly constrained to the baseline of flat ground.
This is the type of advertising we can wholeheartedly get behind. Product engineers of the world, please try to convince your marketing colleagues to show us the insides, tell us why the choices were made, and share the testing that helps users understand both how the thing works and why it was built that way. The last eighty years have brought myriad layers of complexity to most of the products that surround us, but human nature hasn’t changed; people are still quite curious to see the scientific principles in action all around us.
Make sure you don’t bomb out of the video before the very end. A true bit of showmanship, the desktop model of a car is recreated in a full-sized Chevy, complete with “sky-writing smoke” to draw the line. I don’t think it’s a true analog, but it’s certainly the kind of kitsch I always look for in a great Retrotechtacular subject.
When it comes to creating a handling monster, the aim is to create a car that sticks to the road like glue, and is controllable when it does break loose. Having a car that handles predictably at the limit is a big help when you’re pushing hard on track, particularly for an inexperienced driver. And, whether you’re hitting the canyons on the weekend or trying to slash your laptimes, it’s always nice to have more grip. Through selecting the right parts and getting the set up right, it’s possible to hone your car’s cornering ability to make it a rewarding experience to drive fast and hard. Continue reading “How To Get Into Cars: Handling Mods”→