drivetrain
Duawlfin: A Drone with Unified Actuation for Wheeled Locomotion and Flight Operation
Tang, Jerry, Zhang, Ruiqi, Beyduz, Kaan, Jiang, Yiwei, Wiebe, Cody, Zhang, Haoyu, Asoro, Osaruese, Mueller, Mark W.
This paper presents Duawlfin, a drone with unified actuation for wheeled locomotion and flight operation that achieves efficient, bidirectional ground mobility. Unlike existing hybrid designs, Duawlfin eliminates the need for additional actuators or propeller-driven ground propulsion by leveraging only its standard quadrotor motors and introducing a differential drivetrain with one-way bearings. This innovation simplifies the mechanical system, significantly reduces energy usage, and prevents the disturbance caused by propellers spinning near the ground, such as dust interference with sensors. Besides, the one-way bearings minimize the power transfer from motors to propellers in the ground mode, which enables the vehicle to operate safely near humans. We provide a detailed mechanical design, present control strategies for rapid and smooth mode transitions, and validate the concept through extensive experimental testing. Flight-mode tests confirm stable aerial performance comparable to conventional quadcopters, while ground-mode experiments demonstrate efficient slope climbing (up to 30ยฐ) and agile turning maneuvers approaching 1g lateral acceleration. The seamless transitions between aerial and ground modes further underscore the practicality and effectiveness of our approach for applications like urban logistics and indoor navigation. All the materials including 3-D model files, demonstration video and other assets are open-sourced at https://sites.google.com/view/Duawlfin.
An Interactive Hands-Free Controller for a Riding Ballbot to Enable Simple Shared Control Tasks
Xiao, Chenzhang, Song, Seung Yun, Chen, Yu, Mansouri, Mahshid, Ramos, Joao, Norris, William R., Hsiao-Wecksler, Elizabeth T.
Our team developed a riding ballbot (called PURE) that is dynamically stable, omnidirectional, and driven by lean-to-steer control. A hands-free admittance control scheme (HACS) was previously integrated to allow riders with different torso functions to control the robot's movements via torso leaning and twisting. Such an interface requires motor coordination skills and could result in collisions with obstacles due to low proficiency. Hence, a shared controller (SC) that limits the speed of PURE could be helpful to ensure the safety of riders. However, the self-balancing dynamics of PURE could result in a weak control authority of its motion, in which the torso motion of the rider could easily result in poor tracking of the command speed dictated by the shared controller. Thus, we proposed an interactive hands-free admittance control scheme (iHACS), which added two modules to HACS to improve the speed-tracking performance of PURE: control gain personalization module and interaction compensation module. Human riding tests of simple tasks, idle-keeping and speed-limiting, were conducted to compare the performance of HACS and iHACS. Two manual wheelchair users and two able-bodied individuals participated in this study. They were instructed to use "adversarial" torso motions that would tax the SC's ability to keep the ballbot idling or below a set speed. In the idle-keeping tasks, iHACS demonstrated minimal translational motion and low command speed tracking RMSE, even with significant torso lean angles. During the speed-limiting task with command speed saturated at 0.5 m/s, the system achieved an average maximum speed of 1.1 m/s with iHACS, compared with that of over 1.9 m/s with HACS. These results suggest that iHACS can enhance PURE's control authority over the rider, which enables PURE to provide physical interactions back to the rider and results in a collaborative rider-robot synergy.
Exploiting Physical Human-Robot Interaction to Provide a Unique Rolling Experience with a Riding Ballbot
Xiao, Chenzhang, Song, Seung Yun, Chen, Yu, Mansouri, Mahshid, Ramos, Joรฃo, Bleakney, Adam W., Norris, William R., Hsiao-Wecksler, Elizabeth T.
This study introduces the development of hands-free control schemes for a riding ballbot, designed to allow riders including manual wheelchair users to control its movement through torso leaning and twisting. The hardware platform, Personal Unique Rolling Experience (PURE), utilizes a ballbot drivetrain, a dynamically stable mobile robot that uses a ball as its wheel to provide omnidirectional maneuverability. To accommodate users with varying torso motion functions, the hanads-free control scheme should be adjustable based on the rider's torso function and personal preferences. Therefore, concepts of (a) impedance control and (b) admittance control were integrated into the control scheme. A duo-agent optimization framework was utilized to assess the efficiency of this rider-ballbot system for a safety-critical task: braking from 1.4 m/s. The candidate control schemes were further implemented in the physical robot hardware and validated with two experienced users, demonstrating the efficiency and robustness of the hands-free admittance control scheme (HACS). This interface, which utilized physical human-robot interaction (pHRI) as the input, resulted in lower braking effort and shorter braking distance and time. Subsequently, 12 novice participants (six able-bodied users and six manual wheelchair users) with different levels of torso motion capability were then recruited to benchmark the braking performance with HACS. The indoor navigation capability of PURE was further demonstrated with these participants in courses simulating narrow hallways, tight turns, and navigation through static and dynamic obstacles. By exploiting pHRI, the proposed admittance-style control scheme provided effective control of the ballbot via torso motions. This interface enables PURE to provide a personal unique rolling experience to manual wheelchair users for safe and agile indoor navigation.
SpaceHopper: A Small-Scale Legged Robot for Exploring Low-Gravity Celestial Bodies
Spiridonov, Alexander, Buehler, Fabio, Berclaz, Moriz, Schelbert, Valerio, Geurts, Jorit, Krasnova, Elena, Steinke, Emma, Toma, Jonas, Wuethrich, Joschua, Polat, Recep, Zimmermann, Wim, Arm, Philip, Rudin, Nikita, Kolvenbach, Hendrik, Hutter, Marco
We present SpaceHopper, a three-legged, small-scale robot designed for future mobile exploration of asteroids and moons. The robot weighs 5.2kg and has a body size of 245mm while using space-qualifiable components. Furthermore, SpaceHopper's design and controls make it well-adapted for investigating dynamic locomotion modes with extended flight-phases. Instead of gyroscopes or fly-wheels, the system uses its three legs to reorient the body during flight in preparation for landing. We control the leg motion for reorientation using Deep Reinforcement Learning policies. In a simulation of Ceres' gravity (0.029g), the robot can reliably jump to commanded positions up to 6m away. Our real-world experiments show that SpaceHopper can successfully reorient to a safe landing orientation within 9.7 degree inside a rotational gimbal and jump in a counterweight setup in Earth's gravity. Overall, we consider SpaceHopper an important step towards controlled jumping locomotion in low-gravity environments.
The best gifts for cyclists in 2023
Other than a bike, helmet and a few emergency maintenance essentials, there aren't many things a person needs to enjoy a bike ride outside. But having the right accessories can go a long way towards making the experience more fun, more safe and, ultimately, more rewarding. The list of recommendations below cover the gamut of things you can give to the cyclist in your life, from must-have safety accessories like bike lights, to more techie gadgets like bike computers. However, each represents an item the staff here at Engadget have personally tested or swear by, and would make for a great holiday gift. It's an inevitable fact of cycling: at some point, something will go wrong or a part will need adjustment during a ride at the worst possible moment.
Design and Control of a Ballbot Drivetrain with High Agility, Minimal Footprint, and High Payload
Xiao, Chenzhang, Mansouri, Mahshid, Lam, David, Ramos, Joao, Hsiao-Wecksler, Elizabeth T.
This paper presents the design and control of a ballbot drivetrain that aims to achieve high agility, minimal footprint, and high payload capacity while maintaining dynamic stability. Two hardware platforms and analytical models were developed to test design and control methodologies. The full-scale ballbot prototype (MiaPURE) was constructed using off-the-shelf components and designed to have agility, footprint, and balance similar to that of a walking human. The planar inverted pendulum testbed (PIPTB) was developed as a reduced-order testbed for quick validation of system performance. We then proposed a simple yet robust LQR-PI controller to balance and maneuver the ballbot drivetrain with a heavy payload. This is crucial because the drivetrain is often subject to high stiction due to elastomeric components in the torque transmission system. This controller was first tested in the PIPTB to compare with traditional LQR and cascaded PI-PD controllers, and then implemented in the ballbot drivetrain. The MiaPURE drivetrain was able to carry a payload of 60 kg, achieve a maximum speed of 2.3 m/s, and come to a stop from a speed of 1.4 m/s in 2 seconds in a selected translation direction. Finally, we demonstrated the omnidirectional movement of the ballbot drivetrain in an indoor environment as a payload-carrying robot and a human-riding mobility device. Our experiments demonstrated the feasibility of using the ballbot drivetrain as a universal mobility platform with agile movements, minimal footprint, and high payload capacity using our proposed design and control methodologies.
Kia's EV6 is the new benchmark for affordable electric cars
We got our first good look at the EV6 last March and, nearly a year later, finally got to sit in it, drive it, and push every button in the cabin last week during a day-long press event in Northern California. It's the first Kia vehicle to be produced under the company's new Plan S electrification strategy and is expected to be joined by nearly a dozen other new EV models by 2026 - with Kia noting that "All dedicated Kia EVs will begin with the'EV' prefix, followed by a number that indicates the car's size and position in the lineup, not its chronological place in the launch cadence." And that's just vehicles built on the Hyundai Group's (which owns Kia) E-GMP battery-propulsion platform. When the EV6 arrives in all 50 states later this spring, it'll be going up against the likes of the Ford Mustang Mach-E, the Volkswagen ID.4, the Tesla Model Y, the Ioniq 5 and Nissan's Ariya -- not to mention Kia's own Niro EV and its brother from a Hyundai mother, the Kona EV -- also probably the Toyota bZ4X and Subaru Solterra when they eventually arrive as well. The EV6 will be made available in three trim levels: Light, Wind, and GT-Line.
A general anomaly detection framework for fleet-based condition monitoring of machines
Hendrickx, Kilian, Meert, Wannes, Mollet, Yves, Gyselinck, Johan, Conrelis, Bram, Gryllias, Konstantinos, Davis, Jesse
Machine failures decrease up-time and can lead to extra repair costs or even to human casualties and environmental pollution. Recent condition monitoring techniques use artificial intelligence in an effort to avoid time-consuming manual analysis and handcrafted feature extraction. Many of these only analyze a single machine and require a large historical data set. In practice, this can be difficult and expensive to collect. However, some industrial condition monitoring applications involve a fleet of similar operating machines. In most of these applications, it is safe to assume healthy conditions for the majority of machines. Deviating machine behavior is then an indicator for a machine fault. This work proposes an unsupervised, generic, anomaly detection framework for fleet-based condition monitoring. It uses generic building blocks and offers three key advantages. First, a historical data set is not required due to online fleet-based comparisons. Second, it allows incorporating domain expertise by user-defined comparison measures. Finally, contrary to most black-box artificial intelligence techniques, easy interpretability allows a domain expert to validate the predictions made by the framework. Two use-cases on an electrical machine fleet demonstrate the applicability of the framework to detect a voltage unbalance by means of electrical and vibration signatures.
Apple's Probably Not Gonna Buy McLaren, But It Should
Rumors swirl around Apple like exhaust around a race car, and one of the most persistent is that Apple wants to break into the auto industry with an electric, self-driving car. The speculation intensified today when the The Financial Times reported that company is negotiating a deal to buy McLaren. McLaren is perhaps best known as one of the most storied teams in Formula 1, but the company, based in England, also makes sports cars. Very expensive, very fast sports cars. Now, it makes sense that, if Apple is indeed serious about cars, it would buy a company with the expertise to do the job.