Kinematic and Dynamic Bicycle Models#3
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Implement the two vehicle models from Kong et al. (IEEE IV 2015): - KinematicBicycle: 4-state model [x, y, psi, v] with inputs [delta_f, a]. No tire model, valid at all speeds. - DynamicBicycle: 6-state model [vx, vy, psi, psi_dot, X, Y] with linear tire forces. Low-speed slip angle guard. Also adds: - BicycleParameters / DynamicBicycleParameters dataclasses - BicycleConstraints with Table II bounds from the paper - hyundai_azera() factory for the paper's test vehicle - Example notebook comparing both models (step steer) - Pin pathsim>=0.20 - 30 tests passing Ref: Kong, Pfeiffer, Schildbach, Borrelli, IEEE IV, 2015
- Use explicit 2-DOF lateral-yaw state-space form (A*x + B*u) instead of computing intermediate slip angles/forces which caused nonlinear divergence through Coriolis coupling - Remove dvx = psi_dot*vy term (constant-speed assumption) - Adjust C_af/C_ar to total axle stiffness convention (1/m not 2/m) - Balance front/rear stiffness: C_af=126kN/rad, C_ar=80kN/rad - Add double lane change example (examples/example_lane_change.py) - 30 tests passing
- Point README and pyproject.toml URLs to github.com/vvrs/pathsim-vehicle - Fix steering profile: use 2 sine cycles for proper double lane change (move to adjacent lane and return, net-zero lateral displacement) - Extend simulation to 7s for full maneuver + settling
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Adds kinematic and dynamic bicycle vehicle models based on Kong, Pfeiffer, Schildbach, and Borrelli, "Kinematic and Dynamic Vehicle Models for Autonomous Driving Control Design", IEEE IV, 2015.
What's included
Blocks
KinematicBicycle4-state model[x, y, ψ, v]with inputs[δ_f, a]. No tire model required, valid at all speeds including zero.DynamicBicycle6-state model[vx, vy, ψ, ψ̇, X, Y]using the standard linear 2-DOF lateral-yaw state-space formulation. Captures tire slip effects absent from the kinematic model.Parameters
BicycleParameters(l_f, l_r) andDynamicBicycleParameters(adds m, I_z, C_af, C_ar)hyundai_azera()factory for the paper's test vehicleConstraints
BicycleConstraintsdataclass with Table II bounds (steering angle/rate, acceleration/jerk)clip_steering()andclip_acceleration()utility functionsExample
examples/example_lane_change.py— double lane change maneuver comparing both models at 15 m/s with a 2×2 plot grid (trajectory, heading, steering input, lateral displacement)Tests
30 tests covering parameters, constraints, and both models (ODE RHS verification + full PathSim integration tests).
Dependencies
pathsim>=0.20pathsim.blocks.dynsys.DynamicalSystem, following the same pattern aspathsim-chem's CSTR blockLane change Example in Pathview