BEST Seminars

Seminars: 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010

All BEST Lab seminars will be in 230 Hesse Hall (mezzanine design loft), unless otherwise noted. Lunch served for our Friday noon seminar series for students and invited guests. Some talks will be held jointly with the Berkeley Institute of Design seminar series at 354/360 Hearst Mining Building. BEST Lab students can sign up for short presentations.

We are working on being a Zero Waste Lab in 2017. Please adhere to the guidelines. Here is the list of Zero Waste Caterers: http://realestate.berkeley.edu/crrs/zero-waste-events

Ed Zhu, Modeling of Uncertain Restitution Behavior in Path Planning for Tensegrity Robot Locomotion, Fri, Dec 8, 2:00 pm in BEST, 230 Hesse Hall

With  potential  applications  in various  fields such as space exploration  and  search  and rescue, spherical tensegrity  robots are an attractive alternative to traditional wheeled rovers for use in complex environments.    This  is in part  due  to  their  inherent  compliance  and robustness to impact, which may enable rapid deployment by dropping or launching as well as the ability to perform controlled hops in low gravity environments.  To perform such actions in a risk aware manner, this work attempts to model the restitution behavior and the associated uncertainty of spherical tensegrity  robots in various impact  scenarios.  Multiple models are considered and a comparison of these methods  is performed in simulation  in terms  of their performance in trajectory prediction  and uncertainty quantification. The restitution model is then  incorporated  in a path-planning algorithm  in the context  of navigation  missions in space exploration.  Here it is shown that  by taking the restitution behaviour of the robot into consideration,  more conservative  paths  can be found automatically which limit the robot’s exposure to unsafe conditions.  This work concludes by discussing possible applications  of this restitution model as well as future work to improve model expressiveness and path-planning performance.

Elena Duran, Geometris: Designing an Embodied and Collaborative Geometry Game and Understanding its User Interactions, Thu, Dec 6, 3:00 pm in BiD

Presentation of MS Plan II report with abstract: Inspired by the embodied cognition paradigm and after detecting a scarcity of instructional practices in learning about geometric shapes that leverage students’ body-based experiences to foster learning, we created Geometris, a Full-Body Interaction Learning Environment (FUBILE). Working under the umbrella of online embodiment, it provides children with an embodied experience that they can use to ground their understanding of the mathematical concept of shapes. Geometris uses players’ whole-body movements as a resource for fostering dialogue and thinking about shapes. Children play Geometris on a 6-foot square floor mat. Some shapes are projected sequentially onto the floor next to the mat and players need to re-create these 2D shapes by touching pressure-sensitive pads corresponding to the corners of the projected shape. As some shapes have more than four corners, players must work together, adding a collaborative aspect to gameplay. Intending to stay away from the traditional way mathematics is typically evaluated in formal settings, we score play with a picturesque geometric design rather than with a numerical indicator.

As it was mentioned in the acknowledgements Geometris is the result of the hard work of three graduate students: Leah Rosenbaum, Ganesh Viswanathan Iyer, and myself. Each team member contributed in unique ways to the design and implementation of the game. The team formed during Fall 2016 in Dr. Kimiko Ryokai’s course on Tangible User Interfaces (TUI) with the additional guidance and support of Noura Howell, the Graduate Student Instructor. The involvement of all these stakeholders was pivotal for Geometris’ success.

In the first part of this report I will share the motivation that led us to the conception of the game, the foundational work that inspired and guided the design principles and features of the project, and the implementation process we followed to create a working version of Geometris. In the second part of the report I will talk about the lessons learned from the field: the design iterations we engaged in based on interactions and feedback received from players, and the details of a pilot study we conducted to understand player’s experiences and interaction– what Salen and Zimmerman’s (2004) call Play as Experience and Social Play. The learning opportunities that Geometris has to offer are out of the scope of this report but will be discussed in future work.

Directions: http://bid.berkeley.edu/directions/

Julia Kramer, Understanding Human-Centered Design to Improve Access to Cervical Cancer Screening, Fri, Sep. 29 in 230 Hesse

Abstract: Quals practice talk. There will be pizza!

Brian Cera, Inclined Surface Locomotion Strategies for Spherical Tensegrity Robots, Fri, Sep. 22 in 230 Hesse

Abstract: L.-H. Chen, B. Cera, E.L. Zhu, R. Edmunds, F. Rice, A. Bronars, E. Tang., S.R. Malekshahi, O. Romero, A.K. Agogino, A.M. Agogino, to appear in the Proceedings of  the International Conference on Intelligent Robotics  and Systems (IROS 2017). This paper presents a new teleoperated spherical tensegrity robot capable of performing locomotion on steep inclined surfaces. With a novel control scheme centered around the simultaneous actuation of multiple cables, the robot demonstrates robust climbing on inclined surfaces in hardware experiments and speeds significantly faster than previous spherical tensegrity models. This robot is an improvement over other iterations in the TT-series and the first tensegrity to achieve reliable locomotion on inclined surfaces of up to 24◦ . We analyze locomotion in simulation and hardware under single and multicable actuation, and introduce two novel multi-cable actuation policies, suited for steep incline climbing and speed, respectively. We propose compelling justifications for the increased dynamic ability of the robot and motivate development of optimization algorithms able to take advantage of the robot’s increased control authority.

Ying Zhang, Non-Contact Vital Sign Monitoring, noon, Fri, Sep. 15 in 230 Hesse

Abstract: Ying Zhang and Zongyang Xia have received a TechConnect National Innovation Award, which was presented last week in Washington, D.C. at the TechConnect World Innovation Conference and Expo. Zhang is an associate professor in the Georgia Tech School of Electrical and Computer Engineering (ECE), and Xia is an ECE Ph.D. student in the Sensors and Intelligent Systems Laboratory, which is led by Zhang.

These awards identify the top 15 percent of submitted technologies as ranked by the TechConnect Corporate & Investment Partner Committee, and the innovation rankings are based on the potential positive impact the submitted technology will have on a specific industry sector. Innovations are submitted from global academic technology transfer offices, early-stage companies, small business innovative research (SBIR) awardees, and government and corporate research laboratories.

Zhang and Xia received this award for their technology entitled, “Noise suppression scheme based on phase locked loop for non-contact vital sign detection.” They have developed and experimentally demonstrated the use of a non-contact vital sign detection system using phase locked loop (PLL) to automatically suppress the residual phase noise. A PLL is a negative feedback scheme that synchronizes the output signal with a reference. The designed dual-carrier system uses PLL to lock the phase of one carrier’s beat signal to a low-noise reference signal to suppress the residual phase noise, providing a clean transmission path for the other carrier.

When compared to a similar but unlocked setup, results show that the developed system improves signal to noise ratio by 50 percent at 50 cm. The developed system is also used to successfully measure a heartbeat at 250 cm (more than double the distance of the unlocked system) and at four physical orientations. Potential commercial applications for this technology include biomedical monitoring, healthcare, fitness monitoring, physical monitoring of astronauts/drivers/pilots, and search and rescue operations.

See news article on this: https://www.ece.gatech.edu/news/592084/zhang-xia-honored-techconnect-national-innovation-award

Mallory Daly: Design and evaluation of 12-bar tensegrity robots for surface exploration missions (M.S. presentation), Mon. May 1, 2017, at 1:00 pm in Hesse 230

Abstract: The purpose of this research is to evaluate the capabilities of 12-bar tensegrity robots as a platform for planetary surface exploration. Mission-relevant design metrics for mobility and impact capabilities were established. A rapid prototyping approach was used to construct two forms of 12-bar tensegrity robots, the cube and octahedron. Systematic mobility and drop testing was conducted to evaluate the robots’ performance against the design metrics. Through mobility testing, it was found that both the cube and octahedron are capable of rolling in a straight, grid-like manner, which is unique from previous tensegrities made using a six-bar structure, but that the cubical tensegrity’s actuation scheme is more robust to the influence of cable actuation speed and system mass. Through drop testing, it was found that both the cube and octahedron exhibit directional sensitivity but are capable of protecting a payload at drop heights of up to 1.5 m. It was concluded that the cubical 12-bar tensegrity demonstrates better mobility characteristics, but the cubical and octahedral 12-bar tensegrities perform equally well in impact scenarios.

Jeremy (Jer) Faludi: Golden Tools in Green Toolkits: What drives sustainability, innovation, and value within different sustainable design methods? Tues. April 25 noon, Berkeley Institute of Design, Hearst Mining Hall 360. 

If you’ve ever wondered about Jer’s dissertation research, now’s your chance to hear the nutshell version, with no reading required for this PhD seminar.   The title is: “Golden Tools in Green Toolkits: What drives sustainability, innovation, and value within different sustainable design methods?”   Tuesday, April 25, at 12:00pm – 1:00pm in the Berkeley Institute of Design (BID) lab, Hearst Mining Hall 360.

 Directions: – Coming from Etcheverry / Sutarja Dai go straight through Cory hall and turn left to exit, cross the alley and come in the back door of Hearst. Follow the signs up the stairs to BID. – Coming from Wurster, you cross the creek, pass the Campanile, go through Hearst Mining Circle, and into Hearst Mining Hall.  Then cross the atrium, go up the right-hand stairs to the second floor, turn left into the hallway, and follow the signs all the way to the end of the hall. Lunch will be served.

 

Drew Sabelhaus: Trajectory Tracking Control of a Flexible Robotic Spine (Practice Qualifying Exam 2), Fri. April 21 12pm noon in Hesse 230

Abstract: The Underactuated Lightweight Tensegrity Robotic Assistive Spine (ULTRA Spine) project is an ongoing effort to develop a flexible, actuated backbone for quadruped robots. In this work, model-predictive control is used to track a trajectory in the robot’s state space, in simulation. This is the first work that tracks an arbitrary trajectory, in closed-loop, in the state space of a spine-like tensegrity robot. The state trajectory used here corresponds to a bending motion of the spine, with translations and rotations of the three moving vertebrae. The controller uses a linearized model of the system dynamics, computed at each timestep, and has both constraints and weighted penalties to reduce linearization errors. For this robot, which measures 26cm x 26cm x 45cm, the tracking errors converge to less than 0.5cm even with disturbances, indicating that the controller is stable and could be used on a physical robot in future work.

Duncan Haldane: Rapid and Agile Locomotion with Power-dense Millirobots (Dissertation Talk), Fri. April 14, 1:00 pm 6101 Etcheverry Hall

Abstract: The development of legged robots can serve two purposes. The first is to enable more mobility for robotic platforms and allow them greater  flexibility for moving through complex real-world environments. The second is that the legged robot is a scientic tool. It can be used to design new experiments that drive insights both for the development of new robotic platforms and the characteristic of animal locomotors from which they are inspired. This work presents a design methodology that targets the creation of extreme robotic locomotors. These are robots that outperform all others at a particular task. They are used to study locomotion at the edge of the current performance envelope for robotic systems.

The design methodology focuses on maximizing the power-density of the platform. We apply it to create first a rapid running robot, the X2-VelociRoACH, and two versions of a jumping robot, Salto and Salto-1P. In all of these robots, we centralize the actuation such that one actuator provides all the power for the energetic locomotory tasks. A kinematic coupling is designed for each platform, such that the correct behavior (running or jumping) happens by default when the energetic actuator is driven open-loop. The design methodologysuccessfully created two robots at the edge of their respective performance envelopes.

The X2-VelociRoACH is a 54 gram experimental legged robot developed with this methodology that was developed to test hypotheses about running with unnaturally high stride frequencies. It is capable of running at stride frequencies up to 45 Hz, and velocities up to 4.9 m/s, making it the fastest legged robot relative to size. The top speed of the robot was limited by structural failure. High-frequency running experiments with the robot shows that the power required to cycle its running appendages increase cubically with the stride rate.

Our findings show that although it is possible to further increase the maximum velocity of a legged robot with the simple strategy of increasing stride frequency, considerations must be made for the energetic demands of high stride rates.

For the development of the jumping robot Salto, we firrst devise the vertical jumping agility metric to identify a model animal system for inspiration. We found the most agile animals outperform the most agile robots by a factor of two. The animal with the highest vertical jumping agility, the galago (Galago senegalensis), is known to use a power-modulating strategy to obtain higher peak power than that of muscle alone. Few previous robots have used series-elastic power modulation (achieved by combining series-elastic actuation with variable mechanical advantage), and because of motor power limits, the best current robot has a vertical jumping agility of only 55% of a galago. Through use of a specialized leg mechanism designed to enhance power modulation, we constructed a jumping robot that achieved 78% of the vertical jumping agility of a galago. The leg mechanism also has constraints which assure rotation-free jumping motion by default. Agile robots can explore venues of locomotion that were not previously attainable. We demonstrate this with a wall jump, where the robot leaps from the  floor to a wall and then springs o the wall to reach a net height that is greater than that accessible by a single jump. Our results show that series-elastic power modulation is an actuation strategy that enables a clade of vertically agile robots.

We extend the work with Salto to see how the locomotory capacity of an extreme robotic locomotor can be extended without compromising the power density of the platform. Salto-1P uses aerodynamic thrusters and an inertial tail to control its attitude in the air. A linearized Raibert step controller was sucient to enable unconstrained in-place hopping and forwards-backwards locomotion with external position feedback. We present studies of extreme jumping locomotion in which the robot spends just 7.7% of its time on the ground, experiencing accelerations of 14 times earth gravity in its stance phase. An experimentally collected dataset of 772 observed jumps was used to establish the range of achievable horizontal and vertical impulses for Salto-1P. Slides. 

Drew Sabelhaus: Model-Predictive Control of a Flexible Robotic Spine (Practice Qualifying Exam), Fri. April 7

Abstract: The Underactuated Lightweight Tensegrity Robotic Assistive Spine (ULTRA Spine) project is an ongoing effort to develop a flexible, actuated backbone for quadruped robots. In this work, model-predictive control is used to track a trajectory in the robot’s state space, in simulation. This is the first work that tracks an arbitrary trajectory, in closed-loop, in the state space of a spine-like tensegrity robot. The state trajectory used here corresponds to a bending motion of the spine, with translations and rotations of the three moving vertebrae. The controller uses a linearized model of the system dynamics, computed at each timestep, and has both constraints and weighted penalties to reduce linearization errors. For this robot, which measures 26cm x 26cm x 45cm, the tracking errors converge to less than 0.5cm even with disturbances, indicating that the controller is stable and could be used on a physical robot in future work.