This program optimizes a Double A Arm Front Suspension against suspension characteristics using Simulated Annealing with a weighted square error cost function. This program was written to optimize a BAJA SAE car; however, with the correct optimization goals and constraints, this program could be used for a variety of vehicle types.
Provide the program some basics of the car geometry in a json e.g:
{
"tire_radius": 12.0,
"kingpin_to_hub": 6.0,
"kingpin_to_ground": 5.0,
"front_to_back": 60.0,
"pedalbox_width": 8.0,
"preload_ratio": 0.5
}
the program is unit agnostic, but users must consistently use one unit of length throughout.
Additionally, specify a center position and radius of the search space
{
"theta":1.0,
"beta":2.0,
"x_one":3.0,
"x_two":4.0,
"x_three":5.0,
"y_three":6.0,
"z_three":7.0,
"upper_y":8.0,
"x_four":9.0,
"x_five":10.0,
"x_six":11.0,
"y_six":12.0,
"z_six":13.0,
"travel":10
}Theta and Beta are in degrees and define the angle in the xy plane from Point 1 to 2 and 4 to 5 respectively.
Lastly specify target suspension characteritic values and weights for each value
{
"ideal_wheelbase": 32,
"ideal_track_width": 33.0,
"ideal_scrubs": [0.123, 5.678, 7.89],
"ideal_caster_trails": [2.3, 6.1, 1.3],
"ideal_ground_clearance": 0.94,
"ideal_motion_ratio": 1.0,
"ideal_recession_travel": 7.0,
"ideal_camber_gain": 4.0,
"ideal_kp_size": 8.0,
"wheelbase_weight": 0.1,
"track_width_weight": 0.1,
"scrub_weights": [0.1, 0.1, 0.1],
"caster_trail_weights": [0.1, 0.1, 0.1],
"ground_clearance_weight": 0.1,
"motion_ratio_weight": 0.1,
"recessional_travel_weight": 0.1,
"camber_gain_weight": 0.1,
"kp_size_weight": 0.1
}
Optionally, you can pass in an existing front geometry to compare against the optimization generated geometry.
All JSON paths are specified with command line arguments.
Usage: SuspensionOptimizationSA [-g geometry_file] [-c center_file] [-r radius_file] [-t target_characteristics_file] [-b benchmark_file]