Simulating the Effects of a Virtual Motorcycle Passenger on Vehicle Motion and Rider Effort

2025-06-22

Motorcycles, bicycles, and other single-track vehicles are popular but dangerous methods of transportation. While some are piloted by only a single rider, many powered two-wheelers are ridden with a passenger, who may also significantly influence the vehicle's dynamics. Because simulations are a critical component of vehicle safety research, this paper asks whether a simulated, active “virtual passenger” has stabilizing or destabilizing effects on a rider-vehicle-passenger system. This virtual passenger exerts its control effort by moving an inverted pendulum to simulate the motion of a human passenger's torso without explicit knowledge of rider inputs. A battery of simulations in the nonlinear, multi-body Webots robot simulator show that the passenger's control efforts have mixed effects on both rider effort and vehicle stability over abrupt transitions in pavement height. This indicates that the inclusion of passenger motion may be critical when vetting the safety of roadway designs and/or emerging motorcycle technologies like Advanced Rider Assist Systems.

Can the Webots Robot Simulator be Used for Self-Driving Motorcycle Controller Design?

2025-06-22

While several commercial software packages for simulating the dynamics of robot or human-ridden Single-Track Vehicles (STV s) such as bicycles, motorcycles, or other Powered Two-Wheelers (PTWs) are common in the literature, open-source options for high-fidelity simulations of STV dynamics are limited. This paper explores whether the open-source Webots robot simulator is capable of representing the dynamics of STV s with sufficient fidelity to allow for robotic rider design. Data from a small-scale self-balancing PTW are compared with both a linear dynamic model and with simulation results from a nonlinear, multi-body model of the vehicle custom-built in Webots. Results indicate that Webots's physics engine provides sufficient dynamic fidelity to accurately represent the behavior of the vehicle in both simple step response tests and in assisted teleoperation with automatic starting and stopping via a motorized kickstand.

Flammability and dispersion of tritium in confined release scenarios

2023-03-01

Ignition of a flammable tritium-air mixture is the most probable means to produce the water form (T₂O or HTO), which is more easily absorbed by living tissue and is hence ~10,000 times more hazardous to human health when uptake occurs compared to the gaseous form (T₂ or HT; per Mishima and Steele, 2002). Tritium-air mixtures with T₂ concentrations below 4 mol% are considered sub-flammable and will not readily convert to the more hazardous water form. It is therefore desirable from a safety perspective to understand the dispersion behavior of tritium under different release conditions, especially since tritium is often stored in quantities and pressures much lower than is typical for normal hydrogen. The formation of a flammable layer at the ceiling is a scenario of particular concern because the rate of dispersion to nonflammable conditions is slowest in this configuration, which maximizes the time window over which the flammable tritium may encounter an ignition source. This report describes the processes of buoyant rise and dispersion of tritium. Accumulation of flammable concentrations of tritium next to the ceiling is a common safety concern for hydrogen, but this situation can only occur if dispersion rates are slow with respect to rates of release and rise. Theory and simulations demonstrate that buoyancy does not cause regions with flammable concentrations to form within buildings from sources that have previously been mixed to sub-flammable concentrations. A simulated series of tritium release events with their associated dispersion behavior are reported herein; these simulations apply computational fluid dynamics to rooms with three different ceiling heights and a variety of tritium release rates. Safety related quantities from these simulations are reported, including the mass and volume of tritium occurring in a flammable mixture, the presence or absence of a flammable layer at the ceiling, and the time required for dispersion to nonflammable conditions after the end of the tritium release event. These safety metrics are influenced by the magnitude and rate of the tritium release with respect to the air volume in the room and also the momentum of the plume or jet with respect to the ceiling height. Several screening criteria are recommended to assess whether a specific tritium release scenario is likely to form a flammable layer at the ceiling. The methods and results in this modeling study have applicability to explosion safety analysis for other buoyant flammable gases, including the lighter isotopes of hydrogen.

Archerfish respond to a hunting robotic conspecific

Biological Cybernetics · 2021-07-17 · 7 citations

Towards investigating the influence of probabilistic robot motion parameters on archerfish behavior in fish-robot interactions

2021-01-01

Real Time Motion Planning for Path Coverage with Applications in Ocean Surveying

University of New Hampshire Scholars Repository (University of New Hampshire at Manchester) · 2020-01-01

Ocean surveying is the acquisition of acoustic data representing various features of the seafloor and the water above it, including water depth, seafloor composition, the presence of fish, and more. Historically, this was a task performed solely by manned vessels, but with advances in robotics and sensor technology, autonomous surface vehicles (ASVs) with sonar equipment are beginning to supplement and replace their more costly manned counterparts. The popularity of these vessels calls for advances in software to control them. In this thesis we define the problem of path coverage to represent and generalize that of ocean surveying, and propose a real-time motion planning algorithm to solve it. We prove theorems of completeness and local asymptotic optimality regarding the proposed algorithm, and evaluate it in a simulated environment. We also discover a lack of robustness in the Dubins vehicle model when applied to real-time motion planning. We implement a model-predictive controller and other components for an autonomous surveying system, and evaluate it in simulation. The system documented in this thesis takes a step towards fully autonomous ocean surveying, and proposes further extensions which get even closer to that goal. Presenter Bio Alex Brown graduated with a bachelor's degree in computer science in 2018 from the University of New Hampshire, and is pursuing a master's degree in computer science. Before joining the Center in May of 2019, he spent a year on the IT team at the UNH Interoperability Lab and a couple summers as a software development intern at the predictive analytics and data management company Rapid Insight. His research interests include planning, machine learning and artificial intelligence in general.

Investigating the effects of roadside cover on safe speeds for autonomous driving in high-risk deer-vehicle collision areas

Advances in transportation studies · 2020-01-01 · 1 citations

Open-source five degree of freedom motion platform for investigating fish-robot interaction

HardwareX · 2020-03-18 · 9 citations

This paper presents the design, construction, operation, and validation of a robotic gantry platform specifically designed for studying fish-robot interaction. The platform has five degrees of freedom to manipulate the three-dimensional position, yaw angle, and the pitch of a lure. Additionally, it has a four-conductor slip ring that allows power and data to be transmitted to the lure for the operation of fins and other actuators that increase realism or act as stimuli to focal fish during an ethorobotic experiment. The design is open-source, low-cost, and includes purpose-built electronics, software, and hardware to make it extensible and customizable for a number of applications with varying requirements.

nbgrader: A Tool for Creating and Grading Assignments in the Jupyter Notebook

Journal of Open Source Education · 2019-01-06 · 61 citations

nbgrader is a flexible tool for creating and grading assignments in the Jupyter Notebook nbgrader allows instructors to create a single, master copy of an assignment, including tests and canonical solutions. From the master copy, a student version is generated without the solutions, thus obviating the need to maintain two separate versions. nbgrader also automatically grades submitted assignments by executing the notebooks and storing the results of the tests in a database. After auto-grading, instructors can manually grade free responses and provide partial credit using the formgrader Jupyter Notebook extension. Finally, instructors can use nbgrader to leave personalized feedback for each student's submission, including comments as well as detailed error information.

Target capture strategy selection in a simulated marksmanship task

Scientific Reports · 2019-10-01 · 2 citations

This paper examines how individuals track targets that move in relatively unpredictable trajectories. Gaze and behavioural data were captured as twenty two participants learned a simulated competitive marksmanship task known colloquially as the Death Star over six training days. Participants spontaneously selected one of two consistent target-tracking strategies with approximately equal probability. Participants employed either chasing behaviour, in which gaze follows a target's trajectory before a shot, or ambushing behaviour, wherein gaze anticipates the trajectory and the participant intercepts a moving target predictively. All participants improved in task performance measures (completion time and number of shots), but did so at the expense of accuracy in missed shot attempts. Surprisingly, neither behavioural strategy offered a significant advantage in task performance measures, indicating that either may be equally effective in tackling a hand-eye coordination task with complex target motion such as the Death Star.